Sounds a little like gastric torsion (stomach flipping over). Large chest cavity?
My understanding with obstructions is that most dogs won't even try to drink with an obstruction, whereas with torsion you'll get the drinking and vomiting; just can't keep anything down.
Sorry about your loss. I hope whatever you find out helps.
"Tact is the ability to tell someone to go to hell in such a way that they look forward to the trip"