Pylons on Jython
Support more of the out of the box optional components, such as:
Jinja2 is supported on Jython as of version 2.2.1
Jim Baker and Ariane Paola have played around with Genshi on Jython. Its use of pyexpat is the biggest roadblock. Jython now includes a pyexpat, but it's not fully compatible with CPython's (and doesn't support all the features Genshi uses).
Ariane Paola made some progress porting TurboGears 2 components to Jython for Google's Summer of Code. Genshi and SQLAlchemy are the most important pieces that need porting
Older details: PylonsOnJythonOld