Those boards were the right form. The problem they did not realize was their price was 5x what it needed to be to compete.
I've been thinking of how to build educational clusters with chips like these (current candidate is the Octavo SoM that a TI Sitara core, RAM, some flash, an SD controller and two Ethernet ports) that could have a couple dozen nodes, connected by one or two Ethernet switches, all assembled on a single PCB. A bit like the Pine 64 Sopine clusters, but with more, simpler nodes. The built in Flash can be used to network boot the node, eliminating a large cost in external flash.