"The Ni Mee Poo (Nez Perce) Tribe of the Pacific Northwest has been singled out and erroneously credited with developing the spotted horses found so frequently in the Northwest. The Ni Mee Poo themselves, however deny that they developed this breed, but they did love them and traded to acquire them whenever possible."
There's other interesting info about the Appaloosas and Ghostwinds HERE
Take it for what it's worth.
Cool site, thanks for the link.