i've set cross levers up (salsa levers and also the cheapy nashbar levers) to work with side-pull ultegra road brakes and also with old-school mountain cantilevers.
i'm using them as an only brake lever and both of the above setups have worked well.
i tried to set up a bike with contemporary V brakes and had some problems, though. semed difficult to get enough tension on the cable to pull the brake properly. if i tightened the cable more, the brake arms would no longer sit parallel to the rim.
i don't know if it has anything to do with the lever (they are cross levers after all, and i assume some cross bikes use V brakes) or just my lack of knowlege about mountain brakes (more likely).
any pointers on this setup?