These aren't the only things out there of course, but it should get you started and keep your drawing busy. Available in smaller, more digestible chunks at www.htdhorses.com :
how to make horse from polymer clay several fantastic tutorial on horses
Black chestnut Arabian stallion. It looks like a life size Breyer horse!
breyer horses - Google Search
Faran by Josine Vingerling. Looks so lifelike that I first pinned this to my horse board!!
Model horse - both horse and tack are very nicely done
* * Rather rare. At least, I haven't seen many. Creative.
Tackmaker Cristina Brown - CK Tiny Tack - model horse
Little Red Baby Doll, Appaloosa Filly in Texas | Appaloosa Horses for Sale