Well on good bit of news for the Sail Barge is that Hasbro does seem to want to make it. Based on their previous comments. I really think the only shot at it though is a re-release of the OT in the theatres or if it comes into play in the Clone Wars series or both somehow, someway. Then again if they release the films they would probably focus on the same vehicles again - Falcon, X-Wings, Ties, etc. I would hope they would finally get to some sort of Death Star playset(s) or environments.
I guess it would depend upon the price point. If they ever made the Sail Barge it will be scaled down and probably alienate a lot of collectors. Or the price would be so high that it would just go straight to the clearance aisle like the Falcon and AT-TE. Although I think initially both sold pretty well around my area. I don't see tons of these rotting on the shelves. Then again I can find them easily.
Anyway, one of glimmer of hope is they could make it like the Cloud Car and cram in a whole bunch of weaponry on the Sail Barge. I don't know it seems like a long shot but so was the Cloud Car.