That scene where Todd is walking around the hospital saying, "Nothing wrong with that" to everyone he sees was such a Jack thing.

Exactly. That part really made me sit up and go 'OMG CAPTAIN JACK?'. I don't think the world has enough omnisexual characters, really, but two is definitely a good start.

(It's only just occurred to me that hey, if the Doctor is a Time Lord, obviously the Todd must be a Time Lord as well! THE DEFINITE ARTICLE PROVES IT. And lo, the crossover idea is suddenly even odder than it already was.)