I have a "touring" setup that I am running on my road bike with a 10spd Centaur triple Group. I am using a long cage Centaur Road RD with a 11-34t SRAM 9spd cassette. I found a Centaur hub with a Shimano hub body on eBay. I know there are some aftermarket hub bodies available. The combination works like a champ. The remainder of the specs are: Campy Triple crankset 28/39/50t (28 and 39t chain rings are T/A Specialties), Centaur Ergo shifters 10speed setup for the 9 spd cassette using the limit set screws (pitch is nearly identical to the DA / Ultegra 9spd cassettes). I am using a SRAM 995 chain. Although this setup sounds strange it is smooth as glass once it is set up.

I helped a friend setup a similar setup with Shimano using a 105 group with a Longcage RD. Works very well. The 105 was from a setup he had since the mid 90s. I don't think Shimano has a Road RD other than the Mid Cage type. A neighbor had an LX derailluer installed with her Ultegra 9 speed group. A good starting point for compatibility information is Sheldon Brown's site (RIP).