Those Corbin BB's are just too small and expensive ... IMO, althought they look quite nice. Givi/Kappa has the best hard luggage systems what I have seen, so far.
... But, Givi doesn't make racks to Busa anymore. Actually they recall all their Busa racks, because there was occured that subframe problem in -99/-00 Busas. (Well, those subframes had broken also with stock setup, no luggage systems, no aftermarkert exhaust system, nothing. ) Anyway, that's the reason why Givi has but their racks on hold. So, Busa's rack will be on hold until Suzuki recalls subframe for Busa's -99/-00 models. Idea is that all Busas have to have on same kind of subframe (-01 model versions). After that they will make some tests and if the new subframe pases the their tests, they will release that or newer version of that rack again.
Anyway, there is Givi/Kappa compatible racks available under FiveStars brand name also for the Busa.
Found this on suzukihayabusa.org Do a search for corbin hayabusa