Hmm. I already built something similar at chatfor.us I used tornado load balanced by haproxy for the Web servers instead of Django. Backend is mongodb and I use a small tornado driven zeromq to manage passing updates between the front ends real time. That router also does all the db writes. I built it in my spare time (and it shows) just to have a place to take twitter conversation to get around the 140 character lim…
The problem is that, while building the core of this is easy-ish, the end result should be something very complete & easy to stand up. Our prototype functions (barely, mostly just due to a lack of time), but it's not polished or complete. It's not smooth, easy to use/administer & it doesn't include all the little details that go into successful software projects.