I'm not sure if anyone here is into 3d nurbs modeling, but Rhino seems to be the software of choice among many architects and industrial designers doing 3d modeling lately.
While searching to see if a Mac version would be available I stumbled across a beta program they've set up.
I would encourage anyone with interest to sign up for it at http://community.irhino3d.com/
It's great to see a company recognizing the Mac community and it would be a great program to have available on the Mac.

( the standard Rhino site is: http://www.rhino3d.com/ )
While searching to see if a Mac version would be available I stumbled across a beta program they've set up.
I would encourage anyone with interest to sign up for it at http://community.irhino3d.com/
It's great to see a company recognizing the Mac community and it would be a great program to have available on the Mac.

( the standard Rhino site is: http://www.rhino3d.com/ )