Maybe with a greater dual core desktop presence, the power of two 1GHz processors may combine, but at the moment, it's tough to find things that can make good use of dual core, certainly anything that is a likely target for Mini-ITX.
Actually, in HTPC, it might be good for recording on one thread/CPU while playing something else on the other?
There is also a single CPU board with the Unichrome Pro graphics and CN400 chipset supporting DDR400
http://www.viaembedded.com/product/e...herboardId=261