This isn't an answer to the question as such but ....

I was forced to retire my Ensoniq SD1 due to chronic old age (tuning instability)(I thik it;s the power supply!).

I was using this as "master" keyboard with my PSR3k and Yam MU80 as slaves.

The Ensoniq SD1 (like most Ensoniqs) has a very flexible split / layer control capability; in fact there are 12 "zones" available if you want.

So I looked for a "master" keyboard that could give me anything like the capability of the Ensoniq, at a reasable cost, preferably 6 octave, with patch memory, and with at least 3 "zones". It would have been nice to have some knobs, sliders or switches to control the MU80 in performance mode. 88 notes is just too big.

However, zilch.

The A33 fits the bill from build quality and 6 octaves, but only 2 zones....

The key feel on the M-Audio 88 note that I auditioned was horrible, although that has more zones and lots of controllers (but they are mostly useless to me, see below)

The CME items don't store patches. Neither do the budget Studiologic items.

All the "PC USB" master keyboards feel bad, even though some are nice and (also uselessly) knobby.

Nobody at any level has knobs / sliders / switches that are sufficiently programmable to the MU80 correctly in Performance mode. Given that Cakewalk has been sufficiently programmable on the PC to be able to do this for the paast 10 years, this was disaapointing. Where knobs are available, they drive the "easy" options only (standard controllers, RPN and sometimes NRPRN values)

So now I'm not using another keyboard at all and have completely inverted my control strategy.

The 3000 is used as a "master" keyboard but with no intelligence whatsoever; it's job is to send 5 octaves worth of note data out to the MU80. The MU80 has a set of carefully ordered custom performances used to provide "bread and butter" noises; Acoustic / Electric piano / Organ with or without String / Choir / Brass extras. In Performance mode the MU80 has 4 zones segretgated by note / velocity switching so with a bit of care this can be very effective. I think the Yamaha S30 / S80 / S90 have this option; in fact I looked for an S30 (but failed to find one) whilst exporing master keyboard possibilities. I use the 3k for solo voices and sometimes even more layered piano / woodwind stuff.