It's actually a common misconception that a baucher bit creates leverage. To have leverage the reins would need to be fixed, or it would have to have a shank, neither of which the baucher has.
That said, I have a fussy TB mare who LOVES her baucher bit. The hanging cheek holds the bit very still in her mouth, which she prefers. I don't find it gives me anything "extra" though, she goes great in it for dressage, but if I use it going cross country she pulls like hell once she gets galloping and the brakes and steering pretty much go out the window:P
I use this variation of a 3 ring for cross country: http://img.smartpak.com/product/300x300/18111.jpg
and most of the time my reins are on the big ring, but the lower ring is there if I feel like I need a bit extra control. Something like this or a 3 ring could be used with 2 sets of reins so you could only activate the leverage effect if you needed it. A waterford might be something to try as well, the mouthpiece is broken into several pieces and very moveable so it doesn't really give the horse anything to lean on.
As far as dressage legal bits go, a baucher is legal, but you're not really going to find anything with much bite that's still legal. You could go with something with a thinner mouthpiece and see if that helps. You might end up having to switch back and forth between bits, use something like a waterford or a gag for a couple rides, and then switch back to the snaffle. When she gets pulling again, switch back to the stronger bit for a tune up, then back into the snaffle.