I've been riding road, on a Specialized Allez Elite 2005 model, with 105 Triple 9 Speed setup. Have thought of converting to a compact double setup, but not for the $$involved. Recently picked up a 0 miles cross bike, a 2009 model with Ultegra 10 speed double with a 110 bcd cross double crankset. I'm thinking of moving the ultegra bits to my roadie. I'd like to end up with 9spd double on the cross bike, and 10 speed compact double on the roadie.

I think I need to get a compact crankset for the Roadie, and then move the parts over, and a left-side double shifter for the cross bike, then move the 105 9 speed stuff back over there (but I'm running a long cage rear derallieur on the 9 spd) will this work? Am I missing something?