This might be too ghetto for your taste, but Krylon, Rust-O-Leum, and Dupli Color make vinyl spray paint and I can attest to it working well to bond with vinyl and cover up coloring if you're wanting to paint it black. It'll hold up for years, especially since it's not an area where you'll be rubbing against. Just mask it off and spray it on carefully. It bonds to the vinyl so it's not able to be removed afterwards if you want to go back.
Otherwise, yes, I plan on investigating re-covering my seat if I end up not liking it by duplicating the OEM pattern for a new seat cover. The Full Throttle seat is a bit more complicated to pattern than the Icon seat in terms of copying it in different colors of vinyl. But any upholstery place worth their salt would be able to do it. I mess with upholstery as a hobby and that seat cover doesn't really scare me. There's some narrow turns in the seams that would be a pain in the butt to sew (and have it turn out symmetrical,) but professionals shouldn't mess it up.