It was a lot of work, but I could finally drop the 2to3 requirement! The Bottle sources now support Python 2.5, 2.6, 2.7, 3,1 and 3.2 natively. All tests pass. No measurable performance drawback. Full backwards compatible. Its pure win :)
You can test it directly: http://bottlepy.org/bottle.py
Thank to Ralf and Esteban for their help.