Bastien Salabanzi. He was on top of the world with Flip and Vans (and whoever else), but kooked out and stuck with some off-brand Euro companies for well over a decade.
My favorite Mike Plumb story is when he went into a contract meeting with DuFFS wearing a pair of Vans. I'm not 100% sure if it is true, but it is, he kooked himself out of a sponsor during the signing process, which would be an amazing feat.