I've not tried it myself, but the OS2007 Hacker Edition probably gives you more of the "thumb control" features of the 800 (large menus when you use a finger, etc.) Beware that you'll lose some existing functionality (e.g. video codec support).

Some individual apps are built to stylus-free, such as the Canola media player. The Quiver image viewer (recently mentioned here) is pretty cool to play with, too, if you just want to see a smooth, clean UI (although it does include the standard tiny toolbar).