They will absolutely work. I'm using a Tektro RX 2.1 'cross lever for my conversion. You can get a good look at it here:
http://www.pbase.com/flippinghades/image/40613941, or another look here:
http://www.pbase.com/flippinghades/image/40613948 (when it still had two brakes). They work quite well, but they're not the most comfortable of levers. They're a lot more comfy when I wear my full-finger gloves.