Everything is negotiable. I'd prefer to sell the fish with the tank, unless I can find suitable (size-wise) homes for them. IMO it would be a disservice to them to jam them into a smaller tank. Someone contacted me a while back about buying several of the fish, wanting to put them in a 90-g (!!!!) with "intentions" of getting a 150 "soon". Naturally I declined, as the grouper is already about 18" and wouldn't be able to turn around...
If someone wanted the tank without the fish, I do have options for that. A client of mine who volunteers at the Georgia Aquarium suggested that they might be accepted there as donations - so if somebody wanted the tank without fish, I do have some options available.
Jenn