NURBS
Kerry,
Have you tried Yost Group's Skin? It has a lot of the characteristics of
NURBS. The surfaces it produces are spline surfaces instead of NURBS but for
most purposes there is little difference.
With Skin you can produce spline surfaces from lofted objects or from planar
patches. You can't boolean them, and you will have to manually match edges,
but a little creative modelling can do wonders.
Terry Gilbert
Forcade & Associates