Work update. Got something working! At least, we were watching real digital television (the movies "Paycheck" and "The Master of Disguise") on an iBook over a crossover ethernet cable. The datastream is RTP enough that various open source video players with "play from network stream, UDP/RTP via multicast" can grok it. By Monday those multicast streams should be live on our internal development network.
It's too damn hot. I'm drying off under a fan stream, my towels were just movin the not-dry-feeling around, instead of drying me off.