Sorry for not picking up on this thread earlier (Thanks Travis )
I'm probably a touch late now as you've already ordered a few species (from Triffid Park I'm thinking....) but if you are still chasing a few other interesting species I can help you out. I can definitely supply you with some U. uliginosa for a start, and some U. biloba if you wish.
None of mine are grown aquatically, but most are grown submerged during the warmer months.
PM me if you are still interested.