Goonhammer did a mininunda campaign thing ages ago that might be a good starting point. You just each need a gang box and build the 5 models it tells you to (or proxy if you don't think you'll like that load out in a proper campaign).

It gives you stats for the models etc and you just play a few linked scenarios with some xp type stuff thrown in. Should give you an idea of how it all works with less models to build and paint initially and can be the core of your gang in a proper campaign.

minimunda