Best bet is just scouring CL. There are a couple of good-looking NB1's on there for reasonable prices right now. You didn't actually mention your price range, which will significantly impact the responses you get. If you aren't looking to spend at least $4500+ (and more likely $5500+), you have a pretty tough task ahead of you, based on my frequent searches of the local market. Oklahoma tends to be a little cheaper.
Whatever you do, the prices are about as low as they are going to get for the next 9-10 months. Once mid-late Feb arrives, Miata fever hits and everything goes up 10-20%.