Killer Moth is a strange, kinda goofy, but oddly popular second rate villain. Originally, he attempts to become the anti-Batman. He creats the Mothmobile and the Mothcave, and gives Gotham's crimnal underworld their own Moth-signal, with which they can summon his help (for a price). He even has his own millionaire philanthropist persona, Cameron Van Cleer, though this similarity to Bruce Wayne was purely by accident on his part (but clearly on purpose by the writers).
In more recent stories, Killer Moth has become a moth monster creature known as Charaxes, and is pretty much Killer Croc but moth-y instead of crocodile-y.
Pros: Killer Moth, in some circles, is a beloved villain. There's even a Killer Moth Appreciation and Preservation Society with a webpage and a blog (there's tons of Killer Moth info there, so if you're interested I highly recommend checking them out).
Cons: He's a guy in a moth suit. That worked for Arthur, but in a dark, semi-realistic Batman story, it doesn't work so well.
How I'd do it: I guess you could do Killer Moth like the imitation Batman in The Dark Knight, where it's another dangerous copycat, only moth-themed.
Casting Guesses: Old school Cameron van Cleer looks like a young Kirk Douglas. I'm not sure who fits that bill now though. The character could be played for laughs I guess, in the copycat mode, which would open the door to most any comedic actor. Or more likely a no-name.
Verdict: Sorry, Killer Moth Appreciators, but it's doubtful. But I'm not going to say it's impossible. Just highly unlikely.
After The Scarecrow, Ra's Al Ghul, The Joker, and Two-Face, who should be Batman's next enemy in the Batman Begins/The Dark Knight series? Well, as of now we know that Tom Hardy will play Bane and Anne Hathaway will play Catwoman.
Check out the master list for all the villains covered. I've pretty much run out by now. Obviously, there are more Batman villains, but not any of significance that I know of. As of February 2009, no one is confirmed as a villain. Not the Johnny Depp Riddler, not Phillip Seymour Hoffman Penguin, nobody.