In an interview about the format of his "Hellboy in Hell" comics, Mike Mignola had bad news for Hellboy 3 hopefuls: "The biggest problem I see as far as PR for the next billion years is explaining endlessly not only that there's no 'Hellboy 3' movie, but it's going to be explaining '["Hellboy in Hell" is] a series, but it's not a monthly series.'
From the sounds of it, Mignola is pretty resigned. A Hellboy 3 would be nice, but it sounds like Mignola doesn't think it's in the cards.
For the full interview and more information on "Hellboy in Hell," visit Comic Book Resources.