when i heard about normal thief (http://www.scriptspot.com/3ds-max/scripts/normal-thief) it aligns the normals of the cards to the master surface... its often used for leaf cards on trees, would it work on hair cards also so they appear more round? and again its a max script :s
ravenslayer did some kind of 3dsmax script for exactly that i think... looked it up on his fb account it seemed kinda near to finish but he did not uplaod it... maybe he will if you ask him...
sorry english is not my mother tongue :s i wanted to say that even with the script from ravenslayer you would still have to make fibers and bake them on to planes in 3d. As for a full 2d approach i think yours is the best actually...