There are some high end tools like Geomagic and RapidForm that can do this (both owned by 3d Systems) and it will cost you about $15,000.

To be fair, these companies have a larger development staff, and that's in part what you are paying for.

T-Splines, if I recall correctly is extremely limited in the # of polys it can handle. Its not designed as a poly to nurbs converter (although if you have a low poly object it can do that conversion). T-Splines was designed as a tool to manipulate the nurbs surface via a polygonal "cage". Power Nurbs (Power Surfacing) works in a similar fashion.

There is a plugin for Rhino called RhinoResurf from Resurf3d that can do a conversion like Geomagic Studio, for far less $$$. I tried a demo of it in the Rhino demo version, but had some issues that were related to the demo versions.