Biblefic certainly offers some intriguing possibilities. Ari had two Ruth/Naomi Biblefics written for her last Yuletide, and I think it was in the incest/crossgen/underaged porn battle that I put forth Mary, mother of Jesus/Mary, wife of Clopas as a prompt. And now I suddenly want fic about Lot's daughters.

I'd be afraid to offer it without curtailing the characters I offered though.