I have the same problem, see my posts at [http://discussions.apple.com/thread.jspa?threadID=2261542&tstart=0]
Apple says it is the logicboard, since their testing hd could not extract an errorcode out of the dead MBP, so it cannot be the nvidia chip. if it was, the book would still react somehow, at least bring up the startup chime. hm.
What I find puzzling; I let the MBP stay powered on this morning. Black display, no startupsound, no shiftlock light, the led at the front is on like in sleep mode, but not pulsating. so I let it stay this way and drained the battery. it took about 3 hours and the book got fairly warm to the touch. so something is still going on inside, or not?
at least the powermanager seems to work, I connected it to magsafe and it immediatly began to reload the battery, until the magsafe led went from orange to green after like two hours.