A turbo would be too easy and I've done it before so therefor no fun.

Also, a whining supercharger fits the bill in the grandscheme of the bike I'm building.

The fact that bike engines aren't known for making a lot of power low down is completely irrelevant here.
I want as much low down grunt as possible within the boundaries I've set myself.
It would be rather silly not to use a type of charger that produces boost low down because motorbike engines aren't know for making power low down...

Besides: the engine is a 1226 cc engine with heads and cams specced for bottom/midrange grunt. That combined with short gearing and a supercharger will make for a bike that you don't have to rev the tits of to get it off the line!