My B-bike isn't set up as nice as the A-bike... But the B-bike is still faster than I am

In other words, I wouldn't worry about setting a second bike up w/all the same mods, not worth it IMO. What I've got in my two bikes, many people have in just one bike. I've got older R6's though (03's) and you can pick those up cheap... they run hard and they run long. There's also a LOT of data out there on how to set one up for the track.
I guess what I'm saying is that you can choose where to spend you money and in the end maybe you can afford two bikes easier than you think. I bought one of my R6's for $2K, the other for $2.5K... then I put about $1,700 in suspension (total for both) and they now both are set up with RaceTech in the fronts, the A-bike has an Ohlins shock and the B-bike has a Penske. They both came w/exhausts and PCIII's and were already safety wired.
A lot of great deals to be had out there!