Oh as for the other rings, Batman has a story about him being a Green Lantern. I haven't read it. He's also been chosen to be in the Sinestro Corps, but he rejected it. He's not much for Hope, so I doubt he'd be able to wear a Blue ring. He's not selfish, so he wouldn't do great with an Orange ring. He's got some anger issues I guess, but he's pretty good at controlling his rage, so a Red ring wouldn't fit him. He does have a lot of Compassion though, he could probably wield an Indigo ring with proficiency.
--
~Halo Light is my darkness.
http://a.imageshack.us/img443/8466/shadowhalo.png