A few years ago, I purchased a incomplete sporran at a local Scottish festival. It didn't have tassels or a chain, and the cantle was pretty beat up.
I purchased a new cantle from Stillwater Kilts, snagged up some black rabbit fur from a local leather shop, and snagged up some other pieces from a local craft/hobby shop.
The final product:


The original cantle:


Detail of the Thistle decoration I added: