oh ,do you mean that rare Rust fox fur a lot of artists use on foxes ?
i'd maybe try Etsy next ? I sometimes find some rare furs on there I wish i could import lol .

I found some nice ones on Etsy but they are only in small squares. 10" by 10" I'd need a lot of squares to make everything for this set.
=/ And I don't know how to dye my own fur either to make it look realistic fox fur. =(

dye'ing the fur would eventually fade :< i found that out the hard way when i dyed my own grey fur with rit dye .

I'd maybe look for artists who have stock of the MMfox fur in Rust . It is a limited and rare fur ,sadly. (they do have the palomino fox fur in stock but that may be too biscuity/cream in colour for what you are looking for )

I think I found some rust! But the guy is slow at returning my emails >_<