I have implemented a style sheet switcher called UDASSS into my website
What this little gem does is set a cookie so that when the style sheet is changed all of the other pages use the same style sheet.

The change only happens when the alternate style is chosen from the Change Style page

On one of the alternate styles, there is a couple of areas that don’t have styles, but I am working on them, and will update the style sheets when I have finished.

Edit:
This feature is no longer available!