Let the hive mind of Engadget get that for you.
"I'm looking for a wireless trackpad to use with my older (2.5 or so years old) C2D MacBook that's perpetually docked to my home theater. Something sleek, thin, not too small, made of high quality materials. Ideally, it would natively support all of (Snow) Leopard's multitouch inputs, and even more ideally, it would have a charging dock / base. The only problem is that I'm not sure that such a thing even exists. Think you can throw me a bone?"
Just add a wireless keyboard and I will consider to drop my HTPC.
I feel that this and the new WM6 is shaping up nice for MS.