Don't know if this will help, but there is a schematic for rigging up an A2000 keyboard for the A500.
It's posted somewhere here and on the web.
If they're the same interface, or the pin assignments can be doped out, this might be a viable alternative.
Of course, you could chase down a compact PC keyboard replace the guts with the 600 keyboard and extend the wiring to attach to the 600.
Couple of ideas to knock around.
Curtis
