to my knowledge if you look into lightwaves modeling tools you see what advanced subdiv tools could do.

trimming works with subsurf also in maya.

here is a proove:
http://blenderartists.org/forum/showthread.php?t=86077&page=2&highlight=maya+trim

NURBS are good but only for certain tasks. The same is for polygons. I think a mix of nurbs and subdivs would be the way to go.

claas