Danwell
Here in Oz, I have seen on some bands websites that they do advertise surplus/old/redundant, kilts/hair sporrans/doublets/hose tops etc at reasonable prices. It's just a matter of checking the sites and seeing what they have to offer against what you are after. I suppose that you could get in touch with an official of any band and ask about surplus gear. The worst that could happen is that they say "sorry we don't have any" They may possibly know of a band that does though. Good luck in your hunting