Yep, lots of good info already here. The most popular unit seems to be the Vinotemp VT28TEDS thermoelectric cooler, which is what I have. Whatever you get make sure it is thermoelectric and not compressor driven, otherwise you will have a difficult time regulating your RH.
I have mine outfitted with ChasDen's shelves and drawers, and two pounds of Heartfelt beads in mesh bags. Works great.