No, mainly due to the following facts:
The guys, even if they trimmed down and excersised, are too far gone, they gave up on Ghostbusters after the long fight with Bill and the studio, and without Bill it wouldn't be right.
Half of the props are falling apart, and rebuilding the Ecto ain't economically viable anymore.
The fan base is, unfortunantly not Cult Statis, why risk a film for a *pardon the expression* Ghostbusters obsesses web users? Studios want big audiences.
Plus, script wise, it would have to be a damn good script, and not a repeat of the previous two films, an angle that hasn't been covered, otherwise it's old territory.
I'd love to see a new GB film, heck knows I want it badly, but there's too much against a third GB movie to make it work, Sony is more preoccupied with killing off the MIB franchise with poorly done sequels then with pleasing the fans of this community.
Sorry for taking your time folks.