Yep, once you've got used to the extra range that 76 gives you, you rarely want to play anything smaller unless it is a single sound keyboard like a Hammond (and even then, REAL B3 players need two manuals, so that's a 122 note keyboard!).

You can split a 61 as many times as you want, abacus, but you get VERY little range out of each split....

I play a lot of LH bass, and the low E is great (low C is a little TOO low for me, but I hate 5-string basses, too!), plus I need two octaves to play the bass in.... A 76 still leaves 4+ octaves for the piano part, a usable one hand range...

And, less we forget, some of us like to turn ALL the machines off and use our arrangers as regular keyboards. Maybe some of you 61-ers can play piano well on a small keyboard, but for me, and many pianists, even 76 is just the bare minimum.