I know you wanted a full featured one, but the small (through necessity) keeb on the Pocket Reform has a pitch at least that small. Like the original Reform it uses the so-called Choc switch.
Perhaps the same switches and keycaps could be used to build a bigger form factor to fit the full size reform? I think ortholinear will probably be the way to go, because there will not be the oblong keys account for staggered rows in the traditional keyboard.