ASUS F1A75-M Pro F1 Socket Micro ATX
That would be a good place to start. It would allow you to use processor graphics from a Llano chip and not have to worry about using a video card which would disrupt the already tiny airflow and potentially create size problems.
Llanos are good for things like HTPCs. They have enough graphics power to do low end stuff like HTPCs require but not too low as to have problems doing some things and require a stand alone video card in addition to the processor.