Come to think of it, 49 keys on upper, and 61 (splittable) on lower manual would be even better, since, as you say,
"Most of the time, solo sounds, you'll be playing on the upper manual anyway." The instrument could then be made even more compact and lighter in weight, and infinitely more gig-able.
Something similar to the D-Deck Electone.
It also has presets between the keyboards that Diki mentioned.
Ian
[This message has been edited by ianmcnll (edited 10-04-2010).]