I don't like pictureless stories myself, but they won't upload

I knew this info, and had the pictures, but these guys are better writers, so I include a link to their site, but the photos are from other places.

There were several special edition Mustangs in 1967, such as the Mustang GTA and the Mustang Stallion. (only Canadian) While the GTA was simply a Mustang GT with an automatic transmission, the Stallion was a very unique and very rare model with only 8 built.

The Stallion came with either a 289 Hi-Po, 390, or 428; the transmission options were either a 4-speed manual or C6 Select Shift Cruise-O-Matic, , limited slip rear differential, power steering, power disc brakes, Stallion logos, Cougar taillights, and custom wheels. The Shelby G.T 350 still came equipped with the 289 Hi-Po, and the G.T 500 came packed with a 335 horsepower 428 cubic inch V8. The Shelby models in 1967 received more aesthetic changes, with the grille being changed from the other 67 Mustangs to allow for better cooling, and along with a special rear spoiler, Cougar taillights were fitted to the back end to give it a much different look than the standard Mustangs. The Shelby's sold to the general public were al fastbacks, with a select few made as coupes strictly for Trans Am racing. The G.T. 500 also came with a roll bar and the option of racing style harnesses.

The High Country Specials were still offered with production numbers of only 400, and the rarest 1967 Mustang was the Shelby Super Snake. It was equipped with a 520-horsepower lightweight 427 cubi c inch engine with aluminum heads, tuned headers, 780 CFM Holley 4 barrel carb, aluminum intake, oil cooler, remote filter, 4 speed trans and a 4.11 ratio Detroit locker rear differential. This model was a record breaker, but unfortunately, due to the price of $7,500, which was almost three times the cost of a normal Mustang, it was never mass produced. (Only one made)
http://www.mustangforums.com/classic-mustang

Image Via: http://s3.amazonaws.com/data.tumblr.com/tumblr_kpvlhk1jfc1qzpsi6o1_r2_1280.jpg?AWSAccessKeyId=0RYTHV9YYQ4W5Q3HQMG2&Expires=1263958706&Signature=mjvgjFK%2BY436%2BLAw1OLzyjv6JeM%3D

The Mustang had some good looking concepts that didn't make it, like the Milano, this 2-seater "Mustang Milano" and showed it worldwide beginning of 1970 (starting in February), of course also in Europe.The taillamps of this show car glowed green, amber or red, to indicate wether the car was accelerating, coasting or stopping. The hood was a Shelby-style hood with several scoops and the car was painted in "Ultra violet". The rear hatch could be lifted electrically including the rear glass and revealed a matching set of purple luggage, same colour as the seats.
http://www.ponysite.de/fmcog/isis/prototyp/milano.htm

A good website for unique mustangs is http://www.ponysite.de/news.htm, they have pics of a 67 stang that has a GT40 engine, only 21 recently made. Called the Anaconda, GT690GW