Let me just clarify something here - are you talking about tableless skinning? or skinning using CSS only? These are two very different things - If you use CSS as the main criteria to handle your site layout and structure you can still have the content handled through tables, but it's still regarded as a pure CSS skin.
To not use tokens is misinformation - Tokens/Skinobjects are the heart of the dynamics of skinning and connection with the dnn behaviour. If you don't have the 'tokens' you don't get a login, or date, or breadcrumbs, or menus, or logos that make this application what it is.
I am not sure but the site - thecassettes didn't appear to be dnn. The nuvision site - also did not appear to be dnn, and the bearmountain site - does in fact use tables. The NRL site had a HUGE budget - we're talking perhaps hundreds of thousands of dollar, as did the http://www.afl.com.au site which was about 1 million dollars, so they are disproportionate to the majority of sites that are built these days and are more like showcases to show what dnn can do.
Flash integration - well, I have a free skin http://xdnewblue.dnnskins.com (one of several free skins) which has a perfectly formatted structure for you to download for free and learn how the code is written on the page, and you can apply this to any of your own work. There are also modules that handle the integration of flash which many people also use - from http://www.inventua.com is one that I can highly recommend. You can download for free and if you like it you can buy it - it has not limitations or things like that on there.
I feel that for you to benefit from anything do to do with designing and creating skins you will need to learn about DNN. I get asked about knowledge sharing and training, but I don't want to waste anyone's money - particularly design companies who have the traditional roles of graphic designer, developer, marketing person, project management environment. They would be throwing their money away if I was to come in and train them how to skin if the developer and design did not know dnn.
You see, these showcase sites and ones you like are a combination of skills - and behind it will ALWAYS be someone who really knows dnn. someone who can say - no, you can't do this because this module needs to be changed first, or you need to have this type of doc header, or you need to do this in the skin or via css or you need a spacer to hold that there, and maybe a table.
I learnt skinning from the very same documentation that hasn't changed much over years and the skinning engine itself is simply amazing. This is in my opinion, the key factor to why DNN has a lead in many ways for the ability to create virtualy any look and feel you want, and still manage your website. It is not always compliant, but at the end of the day, depending on who your market is, it might not be a criteria that is as important as others. Not that I do not believe in compliancy but that comes at a price.
I was talking to a developer just the other day and we were discussing how to move ahead in the future with the .net2 framework, dnn, coding and no tables. He told me that this could triple if not quadruple the price of a project. I said even a small one - and he said yes because it requires so much testing and while on different browsers, it might as well be different operating systems. That's the complexity of working with pure compliancy and of course behind that we have the lack of design choices which could be used, because of the constraints of CSS. No matter how much it can do, the fact it's interpreted so differently over so many browsers is the killer, unless you strip back to basics.
I have recently updated my site - it's not finished - http://www.xd.com.au and I took a Joomla theme I just loved and tweaked to make into a DNN skin. Let me tell you this - I simply couldn't use the template out of the box. I tried my darnedest not to use tables, but it went to ****e so often I just had to leave it for two months. I can't tell you the amount of hours we have spent - sometimes DAYS trying to get something to look the same in different browsers. Everything is at a cost in my opinion.
I have about 50 free skins, they are all ascx on my site, but the original code for a few might be html. While I agree with Josh on his comments about working in html / xml / css to a certain extent, I think what happens is we now find the graphics person needing to be an xml expert - and this has it's own drawbacks because some of the quirks with dnn mean you have to find all the xml properties (most are in the skinning document) but not all are there and if you use the nav menu - good luck - I copied what I could find from a PDF file into HTML format on my other site - http://www.skincovered.com - (which we're updating at the moment too)
Alot of the fancy things you see in these sites I have to also tell you is put in via html - using the html editor. It's managed at that level. For those who want fancy menus - you can use flash ones for the top and hard code them- they don't really change, but if you want a series of dropdown navigation - and pure CSS I can only recommend investing a few dollars in the snapis menu - There are also menus which are basically wrappers for the common menus we know such as cssplay, sliding doors etc.. but they are set as modules on pages, and let me tell you abou that one - you don't wan't to have inquisitve clients who log in and change the menus or the code.... that's the downside of using these.
I haven't used solpart for a long time - we have lots of code snippets we drop in when people want solpart but now, we only use pure css menus - we have use third party menus like the telerik controls but I found they just dumped a HUGE amount of code on the page - and increased the page size by sometimes 60 > 100k - so again, it's all about knowing what DNN can do, where you can use html, where you drop in a bit of flash, where you can actually tweak until you get the look and feel you want.
I work in the 'pedantic marketing & design agency' space. It wears me out - we have to match so close to the designer's requirements it drives me mad sometimes, but I don't know - somehow we manage to make them happy - but I can tell you it has come at a cost at sometimes, usually compliancy - that's the biggest area where they insist on having a certain look, but we know how to handle it having worked in dnn for close on ... I hate to admit - 5 - 6 years.. (still miles off being a millionaire out of it but I do love this space) And often we have to charge the client more for their demands that I think at the end of the day could have saved them more money if they just didn't want a particular look. However, the end results are quite beautiful - websites that don't look like DNN - that's what I guess I try to get out of skinning for clients - making their site look like what they need and not punishing them for using a framework, but taking all the really good features that DNN has to offer that I still think other applications can't match and helping them create a truly unique site that meets the stringent marketing teams.
Anyway- - that's just my thought on it. I've close to finished some bigger work and quoting / starting newer projects at the moment and I thought I'd take the time to offer some of my thoughts in this space.
So in summarising - download a few free skins, buy yourself a couple of skins as well - we do invest in third party skins on snow if there something that stands out, and get your self the http://www.demo.snapsis.com menu - I did alot of these menus and now I htink I have a library of over 120 menus that we can drop into it.
Read the documentation - i have a CHM file - no good for macs - on my xd website
Open up dreamweave and start looking at the code - there is a pattern - but also spend somet time learning about DNN - that to me is the real secret of good skinning - knowing what you're working with so you know when you look at a job, how to approach it.
Cheers - and rather than looking, just open up some files and start testing, tweaking and enjoying the journey. 
Nina Meiers
Lots of free skins - Really there are..
http://www.xd.com.au - New look and feel
http://modulereviews.com (just updated - content being updated too)