You're crazy, Tundra's can't swim!
No offense, I mean't that in a good way

I just can't imagine taking a Tundra, or any newer model 4x4 for that matter, into water that deep. Buy an old Jeep Scrambler.
Sorry, to answer you're question I haven't seen a snorkel for a Tundra yet, but you would think that companies would finally start making some real aftermarket parts for us soon. The Tundra isn't going to go anywhere so I think the fear part's manufacturers have of being stuck with a back-stock of parts for a truck that was discontinued (T100) will have to subside eventually.