I always think of it as the "forgotten ZX80"
because it's built to the
same
sort of quality level (and, IIRC, was built by ex-Sinclair employees).
It was reasonably unique* in running FORTH from ROM rather than BASIC
(which
probably makes it a rarer animal than a ZX80, too)
* I'm not going to play the "only one ever" game, but I can't actually
think
of another home system which ran FORTH as the primary language...
Hmmm...
Maybe I may be bribed to create a single board for it :) What is the
size of the original mainboard? :o)