Mark
CreativeMountainGames.com
The basic thought is this: Pick a whole bunch of minis that you like that have some kind of link to your campaign and put them in a bag (or box or coffee can or whatever opaque container you want to use). Then have each player reach into the bag and pull out a single mini at random: this represents their PC.
I think I'd make a list and match it to cards, then draw cards.