Are you sure it's the inside you need to get at?
There's a great DIY at renntech on polishing the lenses:
http://www.renntech.org/forums/index.php?showtopic=24285
(I think you have to register though)
If you still have to get into the headlights, modders have been doing this for years with other cars. Nervous work, but somebody figured out the boxster "recipe" over here:
http://www.boxsterforum.com/forums/showthread.php?t=16149
How did I know about these? I have the same issue. Just parked mine for the winter, and I'll be looking into this myself.