I don't see it being any of these. I think they'll got with another heavily demanded figure.
Also, Geldor won the planeteternia.de's nomination for the fans' choice contest. The 2013 sub exclusive will be revealed at SDCC in July, but voting for the fans' choice figure won't take place until the window to buy 2013 subs has closed a few months later. So Geldor can't be the 2013 sub exclusive.