I got my defroster hoses at a vacuum cleaner store. They will cut off what you need from a spool. Cut to a bit longer than what you need - the compression on the spring inside the hose will keep it in place.
That's a brilliant idea. More durable than the "repro" defroster ducting I've bought too - funny as I knew it reminded me of something, but I never keyed in.
For those of us nowhere near a vaccuum cleaner store, they do sell the shop vac type hoses in various sizes at Rona/Canadian Tire and other places.
