In the picture, 4 square closed linear curves being used as profile for a Nurbs Surface produced through Loft.
More over in this particular case I'm using the “Absolute” option, so the Nurbs segments are evenly distributed along the surface, as you can see the segments slide passed the profiles, and are not bound by them.
I've tried something similar with Skin in Houdini, but seems to not interpolate, just do a straight transitions.
I really like the interpolated (not approximated) aspect of SI's surface lofting. And both “Per Span” and “Absolute” modes are really useful; the first for strict control, the second for uniform distribution as seen below.
Cheers