I didn't have the time to investigate the MPEG-4 multi-channel per transponder issue at NAB, but a poster over at AVS made mention of such a technology display:
http://www.avsforum.com/avs-vb/showthread.php?s=&threadid=515000&perpage=20&pagenumber=212
6 channels per transponder using MPEG-4 (H.264 codec, I wonder?) was apparently being demoed.
BTW, V* D* and E* were all mentioned during Apple's presentation on the H.264/Quicktime 7 demo they gave at their main theater on the NAB show floor this week.
From what I saw at the show, all the hardware/software MPEG-4 encoding/decoding/authoring tools are out there, stable and 'affordable', just a matter for E* of the cost/logistical hurdles of upgrading customers with MPEG-4/H.264 compatible receivers...
But to HokieEngineer's point, it's now up to E* to implement. When that happens is anyone's guess, but it may indeed be a while. Here's hoping not.