Any reason to think that this setup wouldn't work? Both the road hydro levers and calipers appear to use the same DOT fluid as the mountain brakes (2013 Elixer 9's in this case).

I am currently running BB7's with Rival shifters. One of the shifters recently broke, and I wouldn't mind upgrading to higer performance brakes since I am anticipating having a set of Elixers as take-off, it'd be convenient to run them with the 10 speed S-700 shifters/brake levers.