I voted Quantum and Woody. It wouldn't be too hard to make at all. It has a good dynamic of characters, a good backstory, and could be hella funny with cool action sequences.
Deadshoot would be too easy to make, it'd be that generic action movie with a lot of killing and very little plot (even though the comic itself has plot).
I personally really want to see (including Q&W) X-O Manowar, Eternal Warrior, Shadow Man, and Harbinger movies. Bloodshot too, if done right.
Sadly, I've only read a few of things but that made it easier to pick, I suppose.
Blooshot would be the easiest to make a movie out of. But Shadowman is the one I'd want to see.
True. Bloodshot could have a nice 80's ish kind of action movie feel to it. Scratch that, I think if you gave it a Predator/T2 kind of feel it could do well.