I just ran across this intriguing ebay listing:
http://www.ebay.com/itm/maltron-keyboard-kit-better-than-kinesis-/172198659229?It's a kit for building your own Maltron keyboard, including a vacuum-formed ABS shell with holes for MX-compatible switches, and a bunch of simple electronics that would let you build a hand-wired electronics (leds, diodes, a prototyping board, copper wire, an Adafruit 32u4 breakout board, etc.). No switches or keycaps included.
Doesn't show the inside of the shell, or a finished keyboard. Looks like it could ber a fun project, although I'd prefer to get it without all the electronics and do that part myself. If these shells were available in quantity, then perhaps someone could put together three circuit boards for it (left, right and center with the control logic). Of course, to do it right you'd need the right and left circuit boards to be flexible PCBs, but I'm sure there's a workaround for that.