Watching the Mozilla Labs discussion on Personas is really exciting. It looks like they have more than a handful of great designers and there are so many different ways this Mozilla project could go in development.
If your interested in getting involved, here are a few links to get you started:

Design details for your Firefox [...]

Firefox Personas is back! I’ve seen a handful of blogs covering this re-launch I guess you could call it all weekend long. It is an awesome project and I am happy to see it is getting a little more time in the sun. Personas are lightweight designs that “skin” the Firefox web [...]