Borg, with your query regarding the User skin changing...
I used to use a script that
http://www.web-sn.com created (not sure where their site has gone though), which changed the .css that was in use, without having the refresh etc.
This is my old site, so apologies if there's dead links etc, but you can get the idea of things by using the drop down box at the top right -
http://www.mortioli.co.uk/%5Fsite/ (you may notice that it does look like it's refreshing when you first choose a skin, but select another, then back again, and you'll see that no refresh takes place)