I'm considering adding a disc fork to my surly cross check and using some avid bb7 road brakes for the front. I've got tektro road levers on drop bars (outfitted with retroshift shifters) I've got all the gear, so cost is negligible. The frame is not built for disc brakes, so I would leave my cantilever brakes on the rear.
I know the modulation and grab will be different for the brakes. Should I be concerned about having different types of brakes on this bike?