Fluid pressure will provide the equal braking that a cable system can't. I can get a lever that pulls two cables, or even make something that allows the the cable to run two mechanical brakes, but it will never be as simple as dual hydros.

I was hoping someone with actual experience with the shifters would offer their advice. By running the front brakes from the left lever, and shifting the rear gears from the right grip, I've eliminated the brake/shift worries.