I don't know the stuff you're talking about, but it strikes me that ventilation hose is usually pretty generic stuff. About all it would have to be is round. Just wander around the store and look for something about the right diameter.
How about dryer vent hose? If that's too big, how about auto defroster hose? Tell us the inside diameter, and we'll find you something.
"Between what matters and what seems to matter, how should the world we know judge wisely?" - E.C. Bentley, Trent's Last Case