From third hand information, I gather that these are the Creata/Winner's Choice molds sculpted by Candace Liddy. Circa 1999, Creata stopped producing them (in the middle of "series III"). There apparently was a copyright violation by a company called "Toob". Breyer bought the line (through Candace, bankruptcy?) and began producing them in 2005.
Appaloosa set (#300114)
Dapples set (#300116)
Released 2006. Photo taken at outdoor venue.
Pinto set (#300115)
2006 release. Photo taken at outdoor venue.
Mini Whinnies Paint set #1 (#4121)
2007 release. Images taken at BreyerWest 2007.
Mini Whinnies Paint set #2 (#4140)
2007 release. Images taken at BreyerWest 2007.
Breyer Meadows Horse Park (#720004)
2006 release, Target SR. Photos owned and provided by CS.