Shimano tiagra flat-bar shifters and brakes will work fine for this conversion or you can use any other brake levers (for cantilevers, v-brake levers aren't compatible with road brakes) if you're looking to save a few bucks tektro makes some nice basic cantilever or bmx levers that might be cheaper than the tiagra brake levers. Any LBS in the world should be able to get the tiagra shifters for a similar price to the one I linked. Check your stem's clamp size and bar size before you order parts (an LBS can help you with this too) Unfortunately they don't make shimano flat-bar road stuff in black.