Want the Nexus 7 home screen to auto-rotate? Here you go!
It works like a charm. No root required. The app can force any app to auto-rotate, and has the ability to do it on a per app basis. I have it set to force auto rotate the homescreen only, with everything else working as normal. It is kind of an unusual UI, but it is familiar to anyone who has ever connected a Galaxy Nexus to a tv.
I think this a better solution than the root method of tricking the device into thinking it has a different dpi screen, which makes the Nexus 7 use the tablet style UI, but makes things really tiny and hard to read in the process.
The app is 7 day trial, and 2.99 to keep if you like it. I'd say its money well spent, especially for us Nexus 7 users who have 25 free bucks to spend on play store stuff.