Hi Nate. From what i've been told, the Maya plug-in can use the texture mapping tools and can also render with displacement. But right now, the Rhino version is early beta, so those features are not available. Not sure if they will become available for a while. Read this thread, with some comments by one of the developers:
http://www.tsplines.com/forum/viewto...3909af39b77a5b
I think the only way to convert your displaced Hex model into nurbs is to convert it from the high-res mesh. Not sure what the limitations are for TSpline conversion. I just converted a mesh of approx 80,000 polys, which took about one minute to process. Then i tried to convert a 1,000,000 poly mesh sphere and totally crashed

...