Kamijo modeled jewelry from Baby Doll (while wearing his regular costumes) in the G&L Bible. I think it was around the late spring/early summer of 2003. In late 2005 he modeled some clothes from Moitie's EGA line for Cure.
I've never seen Kamijo wear anything from Sex Pot (or anything even vaguely punk, for that matter) and really can't imagine him in clothes like that. When he's not on stage, he often wears simple black suits, or brands like Tornado Mart which are stylish in a more mainstream sort of way. Actually, my avatar right now is a picture of him in some of his normal offstage clothes.