I'm not opposed to it, but I feel like even the Riotboard would be going a little too far out on a limb. The RPi and Beaglebone Black are the best known and the easiest to find at retail, which is somewhat of a major concern, since I figure not everyone who might want to build an ALyX would want to dig around and compare SBCs for what is really a simple design. As it is, I'm leaving a lot of the design open-ended for a bunch of reasons; the big one is the fact that I'm using a USB hub as a backplane and power supply, and there's so many different USB hub shapes and designs that I'm not even bothering with creating a design for the back panel.