Self built 650c frame/fork, Trek Stache 8, Guerciotti, Gary Fisher 86 Montare, Schwinn Homegrown
I've seen a quite a few Ti forks. Quite a few custom Ti frame builder do matching frame/fork combos. I've seen it more on MTB applications so I don't think it's an issue of not being strong enough. I just think most larger companies don't touch it cause of the price compared to a carbon fork and the just the amount of people actually wanting a Ti fork.