I've always wanted to do something with Regalus when he was out searching for the horcruxes, but have never been able to think up a logical plot or find someone to play him. I can't imagine him as having many friends, but have always thought that he would likely have become close to at least one person [male or female, really, but female would be more fun to RP, I think] who would be there to help him out along the journey and keep him calmed down when the quest gets frustrating.
Interested? [or, if you're not... If anyone else reading is, let me know?]