Love to use multiple keyboards. On "one nighters", I use an MS-60(soon to be replaced with an SD-5) and an old Yamaha tone generator, driven by a controller, on top.
At my country club job, I use a B-3, 147RV, Suitcase Rhodes on my right hand and a DX-7 on top (very old school, but fun).
My new house set-up will be an XB-7 Hammond on the bottom, an SD-5 in the center and a MicroKorg an top. I'll have a Kursweil digital piano on my right hand. All will go thru a sub-mixer into the PA.
Am just comfortable with a piano on my right hand, and it looks like I know more and am better than I really am!
Ah, "show-biz"!
R.