Can you run 105 or Ultegra derailleurs as top pull, on a cross bike.

Cheers

nope. I use a pulley underneath the mech to loop the cable round

Don't think I've ever seen a top pull road front mech though no doubt someone somewhere has made them.

You can get a bolt on pulley that reverses the cable pull direction for just this purpose though

Thanks, I can run it via the down tube, but going on form with cross races you'll end up with half the field attached to the cable.

Will have to stick with LX thats already fitted 🙁

Get a speen adapter (www.speen.de) and you can use road mechs with top pull frames. I'm running a SRAM red front mech on my MTB.

The speen adaptor looks very trick.

http://www.speen.de/speen*_en/products.html

I use the Speen "Umlenker" adapter on an Ultegra 6700 front mech. Used it to replace a bolt on pulley, much cleaner looks and less to clog with mud. The shift from small to big ring takes noticably more force than with the pulley though I've found – worth it though, for me anyway.