Stan wrote:
I need to put a sofa in a place where it will cover a floor air vent.
pipe or a duct which would be no more than two inches high and would
run from the air vent to the edge of the sofa, which is about two
feet away.

Hopefully, some one else can point you in the right direction, but I do know
they are available. I have seen them in some of those junk catalogs that we
get in the mail on occasion.

In the mean time, have you tried a Google search? Using vent +deflector
+sofa brought up 431 results.