Recently thought about this. Couple days ago I went and sat on the 1000, MV Agusta F4, Triumph 675, Various Ducs, etc. and they all felt so damn small, like a little toy. Yes, I know they have plenty of usable power.
Now I'm not huge (6'3", 220 lbs.) but not small either. They are so narrow I almost felt like I was sitting on a dirt bike...the suspension was actually lofty as I sat on them? I was like, "Where's the meat?"
I think I would have to get something like the BMW K1200S as a replacement for the Busa. But for a track bike, likely a 1000 or 750 GSXR.