i had a full 9 speed ultegra group which i swapped the STIs, cassette, chain and RD to 10spds. the FD and the crank is the original 9 speed version. on the bench the front shifts perfectly but doesn't shift at all when i'm out pedalling on the roads. it seems you need to stop pedalling momentarily to allow it to shift up. LBS has already tuned it for me and i can't seem to convince them that it can't shift up because it does so effortlessly when its done in the shop. i'm wondering if there are any differences between the 9 and 10 speed FD that is causing the upshift problems. would getting a 10 speed compatible FD and crank be worth it?

The cage on the 10spd FD is about 1mm narrower. This might help. I've mixed and matched most 9/10 combinations with pretty good results and even ran 10 speed on an 8 speed crank with a 9spd FD with no problem. This is all standard 39/53 stuff though. Is your FD exactly 2mm above the big ring? If a nickel doesn't fit tight, the gap is too big.