What's your budget? It sounds like a M4/3rds camera is the way to go, but I'm really not up to speed on them. You could sniff around here:
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Personally, I'm a big fan of the Sigma DP1/DP2 family. The Foveon sensors are perhaps the most film-like of anything out there. They also have nearly the same size sensor as a crop Nikon. I took the first one, the second I found on a forum:
