I have never had a job that allowed for that, but it's fun to imagine.
The obvious ones are any job at a clothing optional resort or bathhouse, or a photographer for adult publications. But less obvious jobs...
I imagine working in a gym in a job that entailed going through the men's locker room periodically (like gathering used towels and replacing them, and custodial staff).
Maybe bar-backs in gay bars? A lot of the bars I've been to have the go-go boys change in the stock rooms, and bar backs are constantly going back in there to restock bar supplies while the dancers are changing.
Backstage in a theater, especially dressers? I'm not in theater, but from what I've heard, there's no time for modesty when you have to completely change outfits and be back on stage in five minutes.
Oh, and certain doctors, especially urologists. And hospital staff of all sorts. When I had appendicitis several years ago, the intake nurses had to check my entire body. (I assume it was to check for lesions, sores, etc., in part to report to the doctors who might need to look at it, but also I assume so that I couldn't try to claim that something that was actually pre-existing was caused by the hospital.)
