Mike ,
The two companies that dye and cut rabbit strip are Wapsi and Hareline.
Both supply white zonker strips.
In the case of good deer hair for spinning.
It depends on what you require from that hair as they vary. Most dyes hair is taken from the deer belly, it being white before you start and way easier to dye a pure color.
The absolute best hair in my book for flies like muddlers and those with natural hair is obtained from the Roe deer, which is a species found in the UK and Europe.
It is a very dense hair and flares like you do not believe.
I know that Chris helm and Dave Whitlock love it.
It is not easy to obtain here fro some reason, and that may be due to the fact the deer hides for the fly tying trade are very cheap to obtain here.
Happy tying.
Davy
www.davywotton.com