I'm running Campy Veloce triple (52/42/30) with an Ultegra FD to an XT rear with an XT 11-34 cassette on it. Bar end shifters are in friction mode now, but that's mainly because I haven't had time to dial it in as well as I'd like to for the index mode. Shifts fine.

My main concern was chain slap on the cross member (where a rear wheel would be on a regular length bike) so I wrapped it with electrical tape to protect the powdercoat. So far that concern has been unfounded. The only difficult part I had was figuring out how to use the bottom pull FD on a frame designed for a top pull FD. Top pulls aren't compatible with my current chainring set up and I didn't want to buy a new one. I was able to figure it out with a little help from my LBS. We brainstormed a bit and solved it. My main problem was that the downtube is huge, around 35mm IIRC. So most adapters on the market wouldn't work.

If anyone is planning on using a road set up on the front and needs to use a bottom pull derailluer'. just let me know and I can take some pics to get you started.