My search has been fruitless so far however I have been in contact with a guy who runs a composite company who would be willing if there's a market to make a batch of ready to fit Oval ducts exact size to the fog cap. Obviously have widest possible flange at the back to run as big a hose as possible for cold air feed.
He asked me to gauge some interest wondered if people would be interested at all.
Cheers Quinny