Stylesheet Switchers

I’ve been trying to get this working for quite a few days now but havn’t found anything suitable. Just wondering if anyone has any expertise on a stylesheet switcher (php or javascript) that could change more than one style at a time (doesn’t have to be WP specific).

What I mean is that I want to let the user have the ability to switch font size as well as whether the site has a navigation, whether navigation is on the left or right. The problem arises that when you choose the navigation to be off/left/right and then try to change the font the navigation goes back to the normal mode.

This might sound a little confusing but any help or direction would be greatly appreciated.