I've worked with a few heads, oddly enough it was most prevalent at a high tech company that made computer hardware. The engineering staff was the biggest group, including the VP. They were paranoid sort of, but I looked so much like I smoked that I didn't have too much trouble.
When I interviewed for the job originally I had long hair (no mullet, think more Iron Maiden) and I was thinking of cutting it so I'd have better luck getting hired. I walk in the door, the receptionist had her hair colored a nice light shade of lavender. My boss to be walks in and he's wearing a tie-dye T-shirt, shorts, sandals, sports a full beard, and has a fairly wild head of long hair. In hindsight, the headbanger hair probably got me the job, figured he was hiring a fellow smoker.

I think he still doesn't believe I've never touched it.