This is something I believe is possible, but I would have to see it to believe it. At the end of the series, word was that the 2 of them were not on good terms. Of course, they certainly could have worked out their differences in almost 20 years(Gasp, is that possible it's been that long?

'especially since Pierce Brosnan lost his wife, maybe Zimbalist contacted him, gave her condolences, and maybe they forgave each other for whatever(deaths can sometimes make people reflect on mistakes they made, and influence them to make amends-just a thought) Anyway, I don't know why they'd want to re-visit it, unless it would be that the end of that show did not please the fans, as it was just a "hurry up ending." At the time Brosnan lost the Bond part because NBC kept him to his contract to do the last few eps because there was such a fan uproar(An irony in that fans saving a show for a star actually worked against the star), and Zimbalist was not happy because, it seems, Brosnan was the one who was becoming a star. Also, the guy who created their characters also created "Moonlighting," which got Bruce Willis notoriety, and I remember reading Brosnan and Zimbalist were both unhappy because they felt that the creator was taking all the things that their characters should be doing and writing it in to "Moonlighting."
Perhaps they would like to portray the characters they way they wanted to, do some of their own "closure." If they did a really good job Remington Steele fans might get some closure, too, but I think that would be a tall order.
