Can we improve the LTS-to-LTS Python upgrade story? (again)

Every LTS we're confronted with the Python upgrade story. This is made difficult because there is usually no overlap in Python versions from LTS to LTS. Not that we've ever come up with a very satisfactory solution before, but let's at least discuss it again since if there is anything we can do, 12.04 is probably a good time to do it.

Just to remind us: since there will never be a 2.8, we only have to worry about Python 3. (Doubtful we'd remove Python 2.7 from main any time soon.) Python 3.3 is slated for after 12.04, and it will only be in alpha during this cycle, which is probably in too much flux to put it in this LTS. Extrapolating out, I think it's possible we'd see a Python 3.4 just before 14.04.