Is the pipe standard brake pipe size? If so, any garage should be able to make up a new one quite cheaply. May have to use the original end fittings, so would need cleaning well.
Once off, measure the pipe with string to follow the bends. Get kunifer rather than copper or steel pipe. Copper tends to work harden and can split eventually, steel, as you've found rusts well, kunifer, or copper nickel pipe, is the best of both, strong, but not too difficult to bend, quite corrosion resistant.
If pipe is larger diameter than brake pipe, might still be worth asking local garages.
Unless of course, you've already sourced a new one.