I have had high pressure hydraulic hoses made here for our tractor- I was thinking it would be a cheap alternative to have them do exactly what you are trying to have done- but I have never personally had it done.
I don't see why they would have a problem with this, must be some sort of fear of liability. Maybe just ask them if they can do it, and don't tell them they are for a car- tell them they are for a piece of off-road equipment...
If the metal ends are in good shape, and they can get the proper size rubber hose, I don't see why it wouldn't be just as good as a new hose.
Bret.