I've got an Ultegra 6600 crank and rd with a shimano 9s cassette being controlled by chorus 10s shifters. I think I'm using a 10s chain. I've found them to need a little extra adjusting now and then but otherwise the system works great for my daughter.

My bike has 2005 record shifters,crank and rd with a da cassette and kmc chain. And a jtek shiftmate. Works flawlessly.