Found this compatibility chart on Shimano website today:
http://e-tubeproject.shimano.com/pdf...y_chart_en.pdf
Apparently you can design a "MTB" system with ultegra/DA road shifters, a DA front deraileur, and a XTR rear derailleur. Add on the XTR front junction box (SC-M9050), you can even get rear gear indicator and synchro shifting.
The 11 speed Ultegra FD is not considered compatible in this set up.
CJ