here is how you find nodes not in UDT:
select * from nodes where nodeid not in (select nodeid from udt_job)
I have a custom property 'in_udt' that I sent after importing nodes into UDT so i don't need to do this by looking in the database every time.
Thanks RichardLetts -- that works great. I modified slightly to reduce the number of node fields but it was exactly what I was looking for.