Apparently, Josh Brolin's name is doing the rounds as a potential Jonah Hex. That is a great choice. Makes so much more sense than the last wacky rumour I heard for that part: Jason Statham (but then, Statham's name seems to get connected to every comic book movie going - he's like the British Nic Cage, in that respect). Hex is one of those perfect comics for adaptation, like Blade: the mythos is known and fondly remembered, but doesn't have a unified, rabid, vocal fanbase to offend, unlike, say, The Fantastic Four.
I'm sure evidence will eventually arise to contradict that belief, but what the hey.