There are setups available to allow actuation of front and rear mechanical disc brakes from one lever. I ride with a guy that uses this setup and it seems to to work pretty good for him. Hope also has setup where they combine both front and rear levers on one side.
Hope Tech 3 X2 Duo Disc Brakes - Operate 2 Brake Calipers from One Single Hand
Hope Tech 3 X2 Duo Disc Brakes - Operate 2 Brake Calipers from One Single Hand