Hi Ben,
I'm not a CX rider or owner, so no practical experience here. But I love to watch CX on TV, and I think with all the mud and snow they ride through, disc brakes will make sence!
Believe it or not Hope did this a very good number of years ago by creating a cable converter that allowed the use of drop bar brifters with hydraulic discs. Sadly very rare.
Really like the Merlin,looks great. Ive just made something like the hope version above,there is a company making them in Switzerland iirc but theyre not cheap at 370 euros,heres my version..↲ http://www.retrobike.co.uk/forum/viewtopic.php?t=132792
or if you have plenty of time on your hands you could make on of these... a veloce 10 speed HS33 hybrid lever (rear)...shown here without hood. Stuck together with that metal puttystuff, sanded n sprayed black.