Its hitting the oil pan or maybe worse the engine block, huh.....
You should just try to modify your arm yourself. We do make custom pitman arms, but we wont do any better than what you could do at a shop. We will just take a stock arm, cut it in half, add some metal, weld the crap outta it, and ship it. No warrentee of course. But we really wont have any clue as to what angle you need or how far to drop it, that's why I think you're better off making one over there.
So could you take some pictures of the interference and of course include some engine shots!