elephant-audio: This Left-Right hits thing is worth clarifying a bit. A drum doesn't know which hand it has been hit with, only WHERE it has been hit, and how hard. If what you want is different hit position articulations, they should be called such; if your left arm isn't as powerful as your right, then a lower velocity should be programmed or played. BFD doesn't use amplitude scaling as much as DKFHS, which, as I understand it, has pools of sound for loud, medium and soft velocity groups, and then amplitude scales within that pool. Instead, a 'continuous' range of dynamic levels, with an equally continuous dynamically-local pool of velocity layer neighbours as alternative hits is used.
I find the idea of left and right hits on a pedal-kicked bassdrum especially amusing - or do you mean you have a double kick drum kit, in which case you might have have two physically different drums recorded, or at least two recording takes of the same drum?
I think what toontrack have algorithmically is a valid (if misnamed) way to present a snare as a multi-articulated instrument; it's just a lot of drummers (especially technical session drummers) we've talked to baulk at the idea that they are any less capable of producing a hit with a certain position and certain strength with either hand.