As seen on Ben’s Cycle blog. Follow the link to see pictures of Kremin’s set up.

Problem Solvers Cable Doubler 1:2. Allows one brake lever to operate two brakes.
1 lever :2 brakes

One brake lever to operate a front and rear brake at the same time. The idea has been tried before, from some cheap dual pull levers, to doubling up standard single levers on top of each other on one side, or custom fabricating old gyro cables to pull two brakes. I’ve never paid much attention to the crap people have come up with to get two brake calipers actuated by one lever but this seems to be the best. Mostly because it simply solves the problem, and does so BETWEEN the lever and calipers. Meaning you can use the components you chose. Just add this to the cables.

Ben’s Cycle has them for $39.99

For more info visit Ben’s Cycle