We used one of the little "cube" heaters for years before it finally gave out. It was only about a 6" cube and sat on the countertop. It was a little pricey, but a really nice compact size. I can't find one just like it by searching Google, but there are some a little bigger, though. I thought Camping World still had them, but I couldn't find it. It had wood grain looking metal sides with all the controls on the back. It was similar to this, but smaller.
http://www.epinions.com/specs/Holmes...Ceramic_Heater