My mare is solid and has two blue eyes. Her dam is chestnut with a stripe and her sire is black with a star. Neither have any leg markings. She doesn't have a pinto in her pedigree, except for a few sabinos. She tested negative for sabino1.
What's weird is that she has a full brother with the EXACT same markings as she has... same eyes, same facial markings, even the same leg marking on the exact same leg.
Here's a picture of her:
This pony's right eye is blue (sorry, I don't have a picture of it) and he's 1/2 QH and 1/2 Shetland:
Here's another solid horse (mostly - if not completely - Haflinger) with two blue eyes:
I think maybe a geneticist will figure it out in the future.