if you already have Rhino 4, then you can do many of your "Jell-O" transforms using Rhino's UDT functions. Also there are commands such as rotate face, scale edge, etc... This is not an easy thing to handle in Nurbs, because transforms will rip apart the seams in a polysurface. With polygons, transform functions don't have to worry about retrimming, tangency matching, and surface rebuilding as they do in Nurbs. Polygonal modelers just move vertices, which should be pretty easy. Nurbs require the object to be analyzed, rebuilt and redefined.

Also Tsplines is a great converter, but only for meshes that have a subd-friendly topology. If you try converting from Sketchup meshes, i imagine the results will not be what you hope for...

jonah