I agree that css skins are breakable, but aren't they all, more or less?  When quoting conversions of web templates I'm constantly pointing this out to prospective clients.  Many templates have main content areas designed to be 600 pixels in width... this creates a problem on some of the Admin screens, even with table-based skins!

If you go out and research, really study the resources you might notice there is very little published knowledge on integrating HXTML/CSS with dynamic content.  Most all the examples use little or no graphics, only a background color or in some cases a repeating graphic for "faux columns", etc. and in my opinion seem to be made only for static content.  Many are downright ugly.  Even the better designer templates from BoxedArt and TemplateMonster - those are at least graphically rich, but once you get inside there's no provision for the expansion/contraction necessary in a CMS.  I learned pretty quickly that anything that is absolutely positioned will be thrown out as soon as the Admin control panel is engaged!

So, are we ready for XML/CSS skinning?  Not yet, but we take a step at a time, do our diligence, learn and experiment some more. Hopefully the core code and modules are being modified in this manner as well, and some point in the future DNN will have this capability.

A related question... in your opinion, should it be necessary for a DNN site to validate while in Admin mode, or not?

Sam, the skin you mentioned has serious problems if you narrow the browser window.  In IE7 and FF, the sitemap/login section wraps to under the menu as you drag and the login part will be remain wrapped.  The container titles to not stay in their area as the text overlaps into hte next container.  On various resizing, the Sitemap/Login will remain wrapped under the menu.   Most of this could be fixed with a minimum width statement to make sure it does not get into that situation of being too small, but not all browsers support minimum width.

This is the problem with CSS, it is not built for overflowing content.  It seems those who defined the standard did not think content should control its parent.  Big mistake, huge!  You should have an option to allow the bounding box to expand if content requires it, but I guess that is one of the reasons tables are so popular.

As long as you have full control on everything displayed and you plan to stay inside the content boundaries, CSS can still make a nice site.  But if a person has any dynamic data on a site such as a blog, forms, guestbook, ect, then there is a chance a site will look hosed if someone adds too wide of content, or they switch to a font size the pushing the text outside of its boundaries.

From what I can see though, it is just safer to build skins with a table layout and make sure to count on the frame possibly stretching.  Makes it easy to generate skins and much less headache.  Once things like CSS 3 comes out and is implemented by all the major browsers, things might be different, but as is, with the current state of CSS and browsers, it is a hard road.