ask YC: youtube clone; python or ruby framework?

I've been using rails for the past 2 years, and have had mixed feelings about it. I ported two rails applications to MERB, because I'm no longer using ActiveRecord, so most of the other stuff in Rails also seemed unnecessary. Prior to ruby/rails I used python (straight up mod_python) for a couple years.

I am starting on a new project where I need to make a video site. Think youtube with limited users and functionality. My initial plan was to do the front-end in MERB and the back end with ruby hooks around our custom video server (c++). However I vaguely remember that writing wrappers around c++ was easier in Python. Thus I thought maybe I could just do the whole thing in Python. I don't really want to use Django. Is there anything similar to MERB in the Python world? Or should I just use MERB for the front end and then use whatever fits best for the video processing. THANKS.