been done, was crap....
because disk levers have smaller pistons, its moves a lot less fluid, so you have to set your brake up extremley close to the rim, so even the slightest buckle will make it rub.
Also because of the piston ratio the lever will be about as stiff as cooked spageti, sponge city!
Also, the resevoirs dont have any say on poiwer, they are there to allow for fluid expansion from when the fluid heats up from going down hill and so on, the fluid can go in there rather than pushing on the pads and eventually locking the brake.