Two things, that I'd like to contribute.
A new-name suggestion, if it comes to that...
"Open Modular Card System", stylized "OMCaS". (Pronounced AHM-cass) It's, from what I can tell, a fairly accurate descriptor, and the acronym is fairly catchy.
...and an idea for further expansion. Rather than have a single CPU card that plugs into a carrier board with lots of stuff, why not have *multiple* cards -- both as the "motherboard" and as the expansion cards...? ;) Key them differently, and then all you need is a mostly-passive backplane ("mostly" because it would obviously break out some of the ports) and a pile of Cardbus connectors.
What do you all think?