Yes it is the dark templar. I had the opportunity to play with them at blizzcon. Originally, i thought the concept art for the unit was a hybrid unit itself.

http://www.starcraft2.com/art.xml?s=37

With the zerg-like armor designs and lower jaw, mixed with the protoss scales and psi blade it appeared at first to be a hybrid. I embarrassingly inquired about this artwork at the sc2 panel, where it revealed otherwise.