Best place to start for vintage clothing is
here, but I'm not sure if they have anything for the body builder to be honest. They do, however, have quite a bit of nice vintage stuff from the old West type era, for both genders and all ages, so if you can't find anything for the body type you're looking for, at least it won't be a total wash-out for the other areas of sim apparel. The best place to look over there is
here, under the prairie theme.