The Microsoft Xbox 360 HD-DVD drive works (its USB 2.0 and about the size of an external plextor drive, but good looking). I have it (attached to a large HDTV and 360, lol) but I have plugged it into my PB and it gets registered. Problem is, there is currently no software that reads it, once there is, then your set.
BTW, HD-DVD looks much better than Blueray (my neighbor has both on a 100inch screen with a 1080P Dreamvision projector, ($15K) and a denon reciever, amp, and preamp, along with the Samsung player and the Toshiba HD-DVD Player. The Toshiba looks a lot better (hence why I bought the microsoft player for my...small in comparison 60 inch Sony, lol).
Go with HD-DVD, get an Xbox 360 (makes up for the lack of games on mac, because I refuse to run windows and Xbox360 sorta makes me feel like im using mac OSX, very intuitive software. Pick up the Xbox 360 HD-DVD drive when you get a chance (remember its a reader only).