So theoretically, could every level from the four game styles be 100% recreated?

So someone could recreate every level in SMB, SMB3, SMW & NSMBU so they would all be available in Super Mario Maker? That would be pretty amazing, but can anyone think of any obvious levels that could pose a problem, I'm pretty sure a lot of SMW levels made use of diagonal pipes, and I haven't seen any footage showing them.