I know Lockhart Phillips also makes adjustable ones.  My cheap ass just bought TL1000R foot pegs.  Gave me the extra leg room I needed and match the rear pegs.
I have the Vortex rear sets, if I had it to do over again I think I would go with the Attack rear sets. Vortex makes a great product the quality and workmanship is top rate. The two issues I have with the Vortex rear set is that they are not adjustable and there is not a bracket to connect the rear brake light plunger to. When I received the rear sets I called Vortex and was told that there rear sets are for race applications only and that was the reason the rear brake light bracket was not part of the package. Currently I do not have the rear brake lights connected. The problem with this is that in Texas you have to be able to turn the brake light on with the rear brake pedal in order to pass the state inspection. Currently only the front brake lever turns the brake light on. When I had my bike inspected I was able to get the guy to overlook the rear brake issue.

Spiegler makes a brake light switch that allows for a workaround for this problem. Another option would be to weld a bracket on the inboard side of the rear set to attach the rear brake master cylinder to.

There are many companies that make rear sets for the Busa. Before you spend the money I would call the manufacture and find out if you can install the rear brake light bracket on there product or come up with some kind of workaround.