note: I'm NOT talking about tangent space normal maps.
UDK & marmoset toolbag can use "direction" maps for anisotropic shaders.
I'm able to get a correct direction map for a planar surface by just rendering in camera space by connecting a samplerInfo nodes tangentVcamera through a setRange node(to compress the values from -1,1 to 0,1) to the output color. (sufficient for hair planes)
However using transfer maps either bugs up the results, or doesn't account for the target meshes tangent orientation.
I fear the solution is either have someone compile a new shader type from the API, or that it's not possible in maya.