I have seen fabric fire hose thrown away in lots of a thousand feet. When it gets old to a certain point, out it goes. So where to look for it?
I tried eBay, and found a bunch by searching on the words "fire hoses" or "fire hose".
I had similar results with Craigslist.
It looks like scrap fire hose will cost about a dollar per foot.
So trying fire stations is a good place to start. Also think about trying the city's corp yard where they keep their second-line fire trucks and other utility vehicles. Try the U.S. Forest Service on East McDowell Road. It's either going to be jackpot or nothing. But you might get leads.
Something that might work, at least for a while, instead of fire hose would be a used serpentine belt from a V8 car or truck. Those are fabric-reinforced and can be bent over and doubled. But old fire hose is a great idea.