Technically, any horse with any white facial or leg marking carries a pinto gene. Tobiano alone doesn't put white on the face, so therefore any horse with white on their face carries overo. Overo is the pattern that causes blue eyes, and although it isn't fully understood which type of overo causes it, most people assume it's splash.
Pretty much every breed out there carries overo minimally. The odd Friesian with a small white star proves that even they carry it. If you look you can find pictures of solid horses of almost any breed with blue eyes.
Here are the photos of my mare's ancestors: Clouds Mystique W Missouri Fox Trotter
Nobody looks like a classic splash. Most horses are solid, and the few horses that have body white look sabino. But splash is there somewhere in a lot of those horses, because it gave her her blue eyes... (BTW - excuse the random warmbloods... somebody screwed up)
Tobiano and frame don't typically hide as well as splash and sabino.