I'm not sure when the Bat and the Clown had time. I saw plenty of UST, but no opportunity. But Dent/Wayne could be a guilty secret for both of them, explaining why they were so gung-ho on "gotta get married, NOW!"
And yeah, a lot of pairings are, "I could totally see that. Hmm. I hope someone writes it someday. Now, what was Snape doing this week?"