Over my diapers, I like to wear boxer briefs, long underwear and/or men's athletic tights with extra padding inside, and then two or three pairs of sweatpants over those. The long underwear makes my diapers and padding feel even thicker. And I like sweatpants over diapers; men's sweatpants seem to be made for diaper lovers.
I would like to try some bib overalls over my diapers sometime though.