Which I think is pretty revealing about the state of Twisted and gevent.

I know from experience that gevent is not in a healthy state of maintenance. There have been some recent commits that indicate it might get better eventually, but I would not design new code to use gevent.

A subset of twisted is already running on python3... enough that projects are going into production with twisted on python3.

Full python3 plan for twisted here: http://twistedmatrix.com/trac/wiki/Plan/Python3

They really are one of the slowest projects to update.