I'd be inclined to agree with Crash on this. Look at all the new specs: PCI-ex, which is serial, SATA, which is serial. Mobo makers learned its easier to go fast and narrow. And I think the failure of RDRAM was largely due to Rambus' hamfisted relations with other companies. If a new serial standard usable by all came out, I think it would be adopted. And yes, it may be a PCI-EX-like scalable architechture. Want dual channel, add another lane.
"It's too late now anyway. That song is stuck in my head and the only way to get rid of it is to blow it out. With a bullet!! - Carl