Weird West might be right up your alley. I don't know if it has been converted to d20 or not, but you could probably find the d20 GURPS version and adjust accordingly.
Also, if you are a fan of d20 Modern, I would highly recommend Sidewinder: Recoiled. It is humanocentric and magic-free. In a game I plan on running, I added "Mystic" from the Urban Arcana rules to simulate magic-users/shamans; they have priest spells but no healing magic, thus necessitating doctors, surgery, and time for healing. As a Hunter of the Dead, you might consider allowing him the Shadow Slayer class from d20 modern and just change the name for flavour. And heck, why not add in the Occultist as his sidekick? You'd have a Van Helsing and priestly follower-guy type relationship: one guy beats on the monsters, the other tells him everytihng he needs to know about them and can help out here and there with an arcane item or two.