Best costume ears, ear models to jumpstart animatronics project?

[Aaron]

I'm contemplating a costume project. One of the things that I would like to create is a pair of ears that reacts automatically to the positions and volumes of sounds relative to the wearer, perhaps also to jarring or sudden movement. Something that would really help the design along would be an existing pair of Na'vi ears that I could play with and make partial casts of. Has anybody here found anything that they really liked?