Hmm... there's a lot of cool prestige classes that could fit the bill, but what about Horizon Walker? Not obscure at all, although certainly not an optimized PrC, and it has no fear elements. It does technically have a caster level for the Shifting terrain mastery, though, so probably not.

It could also be a psionic class, since it doesn't have any CASTER levels. That could be a lot of fun.

But personally? It's specific enough that I doubt we'll ever see it, but I'd like to push for Eye of Gruumsh. I don't know why - I don't have any great ideas to go along with it or anything. It's just such a mess, I can't help but want to see it get some IC love.