I would suggest sourcing vintage furs from eBay, swap meets (flea markets) or local thrift stores. You could always find a nice fur collar on an old sweater/garment and rehome it. ;)
I was going to suggest Etsy or Ebay for on-line vintage clothing - often find coats, collars or hats of fox or mink listed. Otherwise, perhaps an advertisement in a local paper or on-line marketplace might come up with something - amazing what people have stored away.
I googled "fox fur pelts" and received many hits, including: http://www.fursource.com.
Hope this helps.
A tip re fur - never store in plastic bag especially in sub tropics as it will fall apart - lost the lot one year.
I've been lucky enough to get old mink stoles from 'aunties',and from my 25 yr old beaver coat . I've stayed away from resale shops, because it can be pricey to have it cleaned. The furriers use a tumble method of sawdust and special cleansing agents to get it clean, then glazed. As far as washing, I tried to dye fur once and it completely fell apart ;/
You may also have friends to would love to donate their old, out of date coat in lieu of a hat!
Hope this helps