I'm surprised no one mentioned this site! They have BILLIONS of colors.... well, okay, not billions, but a lot!
http://www.mendels.com/fur_solids.html
Thats the link directly to the order page. There is dark purple in there too, and they have their products seperate by length which is sooooo nice when your in a hurry and hate trying to figure out what your getting. I have received several samples that they offer so that I could check out the quality and it's pretty decent stuff. Better than the fur I'm still trying to use up from ebay.
If your strapped for cash and only need a little, I do have a very dark purple in a high pile (long) if your interested. E-mail me and I can send you photos.
-Michele