OK, so I bought a used 'Dale MB tandem (a '96) with cantilever brakes and flat bars. Wanted to put drops and something with more stopping power on it (riding it on the road - I know, could have just bought a road tandem, but this was a deal I couldn't pass up).

Sooooo.....

Put 105 STI on it (off another bike), and then, per many forums, added V-brakes with a 'cable doubler'. They worked very well. However, then decided to do some other jiggling around, which required removing cable inner. Also removed cable doubler, just for giggles, and it works fine still!

So my conclusion is that one can use V-brakes with Road levers, and that which I have read about road levers not having enough travel is not correct.

Notes:
1. we live in a hilly area and yes, we use our brakes copiously
2. front rim is very straight, about 3mm tolerance between rim and pads. Might explain need for small amount of travel
3. left the doubler on the back one. Don't know why. Feels like the longer cable might need it?
4. V-brakes are the $14.95 ones from Performance (sorry Nashbar! I bought all my other stuff off you). Man, they are bomb proof, light, and cost less than dinner at Carls Jr.