Crossovers are my favourite things ever, so I was just wondering, what sort of crossovers would folks be interested in the hypothetical universe where all is possible?

This doesn't have to just be Marvel and DC (although I'd pay to see Matt and John Constantine together) - I for one would love to see Karen and Claire as members of the Rat Queens (Foggy as Orc Dave!) or Matt as Hellboy just for the giggles.