I think that Dwight is open to anyone who can convience him to sign an extension now that the Nets are out of the equation.
A nice sit down dinner with Danny, Doc, KG, and Bill Russell should put things into perspective. 
Even if Howard totally switched course and said he'd love to play here... and even if Orlando decided to just say yes to any offer... we're still bound by the CBA. Would could we
possibly offer that would work under the salary cap? It would have to start with Pierce, or at least
two of Rondo, KG, and Green... and for KG and Green, they'd need to agree to a sign-and-trade.
Take into account that there's no way Orlando is trading Howard without getting rid of at least one bad contract, and it gets much worse.
About the only thing you could do would be Rondo, Green, and Johnson for Howard and Jason Richardson. I certainly wouldn't make that trade if I were the Celtics, and yet I doubt Orlando would make it either.
Bottom line is the Celtics don't have the assets Orlando is looking for. Oh, and DH12 doesn't want to play here.