Bulma x Roshi doujins are always good. There are some old Bulma x Roshi doujins that never got translated from Madoromi Youenjou. Maybe we'll see some better ones later.
@The Chronicler: Trust me, if that was Bulma's daughter, and she was standing with Launch, there would be no question about it. Because Launch would also be old enough to have a teenage daughter. And while I suspect she would age better than Bulma, she would still age.