Not that i know of, i heard of people getting wmv working on 2000 units after a ppc tweaked windows media player, but never an hpc pro....atleast you can play WMA, im stuck with the hum on the Aero
*sigh* I wish there were.
The PPC hack for HPC2000 is just awful. I can never get it to work. The information exists out there for someone to port it. It's just a question of finding a skilled enough developer to do it.
For the time being though, as thcrw739 said. There isn't one. For DivX and MPEG you're covered though.