Hi Peter - I know some of the people here would rather walk over broken glass than recommend one of my sites 
but Here - http://www.dnnskins.com/free-skins.aspx There are over 50 free skins to download.
The skins that Timo mentions - from the 3013 buld were not competition skins but actually skins donated by people at the time, but some of the skins blew the build out from 5mb to a whopping 13mb - it was rather big, so that was dropped quickly.
I have a brief overview on the skins here -
http://www.dnnskins.com/ninas-free-skins.aspx
http://www.dnnskins.com/free-3013-skins.aspx
http://www.dnnskins.com/free-competition-skins.aspx
http://www.dnnskins.com/free-dnn-skins.aspx
This might give you more insight to how they came about.
On http://free.dnnskins.com is a list of all the skins and you can navigate through them to see them all online.
I have as faithfully as possible, upgraded them through DNN 2, DNN3, DNN4 to DNN 5 packaging. We only support the DNN 3,4 & 5 versions online, and they are separated so you can browse through them individually. I use the Catalook store as a catalogue to manage them, so you just add to cart like any other download store, but of course they are free.
Each of the DNN 4 skins has the original file from it's prior upgrade and the licensing, if there is any, belongs to that person.
I setup a facebook page HERE - but that's work in progress, although we have another free skin online which I will be introducing later.
So Peter - there are a ton of free skins, well, not a ton I guess but these are at the very least, current and tested and able to be previewed before downloading. There is a catch, I ask for registration because I have to pay for bandwidth,and in Australia, I pay for bandwidth, at lest 2.50 per mb over my limits, and I can't afford open slather on downloads as well as paying my staff to keep the skins updates.
We have some big plans ahead -I won't share them all yet - they're not ready - but I hope this gives you a bit of inspiration.
You can also buy a skin HERE - if you so wish, and in the future we'll have a few more online from others to buy so we are excited about this too.
I hope this helps.
Nina Meiers