Eventlet or gevent or Stackless + Twisted, Pylons, Django and SQL Alchemy
You might want to check out:
Eventlet and gevent are not really comparable to Stackless, because Stackless ships with a standard library that is not aware of tasklets. There are implementations of socket for Stackless but there isn't anything as comprehensive as gevent.monkey. CCP does not use bare bones Stackless, it has something called Stackless I/O which AFAIK is windows-only and was never open sourced (?).
Both eventlet and gevent could be made to run on Stackless rather than on greenlet. At some point we even tried to do this as a GSoC project but did not find a student.
Answering part of your question - if you look at http://speed.pypy.org you'll see that using twisted on top of PyPy may give you some speedups. This depends of course on your workload, but it's probably worth checking out.
Cheers,
fijal
I've built a little real time web app on top of eventlet and repoze.bfg (I gave up on django quite a while ago). I've found eventlet and monkey patching to be just as easy as Ted says.