One of the best things that I did was exactly what you're doing, to keep a large portion of gear in a different room. That limitation forced me to develop ideas where, before, I was getting lost in the options. Now I have to make solid decisions to avoid running upstairs again and again.
Here's a list of keys:
SCI Pro-One
SCI Prophet 600
Kawai SX-240
Moog Opus
Realistic MG1
Wurlitzer 200A
Janssen upright piano
And I just picked up a Korg Monotron the other day. That sort of counts, right? I also have an SCI Tom drum machine; not a keyboard, but a neat and nerdy sound-maker nonetheless!