good - grind the cases a little on each side of the mount point...pretty easy
bad - rework the frame shock mount point to work with the SSSA (Single Sided Swingarm Assembly), in other words the SS swingarm and the SSSA of a SBK have different mount points on the frame...not too bad if you can weld or can out source it
ugly - SSSA is shorter than the SS swingarm so handling could be off...I don't know that much about motorcycle handling charactistics so...

Try search again, but this time for SSSA. And make sure you choose the 'Search in>> Post Bodies (Return a post listing, slower)' option. More info there.