A-Body Holy Grail???

and don't forget the extreme rarity of 340 and 383 A body convertibles, Dart GTSs and Barracuda Formula S.
Then theres the Barracuda based 69 Savage GT fastbacks (and maybe a convertible or two) There were only about 14 made (one with the 440 and the rest split between 340s and 383s.
Another possibility would be the 68 Barris Barracudas. They were your basic Formula S Barracuda fastbacks but with "dealer installed" customizing kits which included George Barris designed fiberglass trunk lid with molded in spoiler, fiberglass scoops on the C-pillars, fiberglass hood inserts, custom wheels, and fake side pipes. I know a guy that has one (you may have seen it in Building T at Carlisle). I believe only two are known to exist.
Then theres the M-code 440 Cudas and Darts, the GSS Darts, and the Hemi Super Stocks have already been mentioned as have the Ghias.
There are also movie or TV A-bodies. The Mannix Dodge Dart GTS customized by George Barris, Korky's Cuda, and the Fireball 500 66 Barracuda. Or maybe one of the factory customs like the Daroo Dart or the Rapid Transit System Duster.
Other contenders would be the rare and unusual A-bodies from countries outside the US and Canada.
There are certainly enough interesting A-bodies for everyone to have a different choice of ultimate A-bodies.