A large part of the reason you have not found anything is because those Mustangs were not very desireable. And because of that, those that have or had went to the salvage yards had their front suspension gutted out and the rest crushed. To have t-tops, you either have a GHIA if it is a coupe, or a Cobra/King Cobra if it is a fastback. Since that body style to many of us was a re-skinned Pinto, the best bet would be to try someone that specializes in Pinto parts. No, Pinto sheet metal is not the same. The trick here is that people that liked the Pinto usually liked the Mustang II. And since the 2 were so closely related, one fed off the other as far as parts sales were concerned. Someone mentioned the Paddock. It would be worth a try. However do not get your hopes up because the Mustangs they specialize in (or did) usually skipped the Mustang II years. I wish I could be of more help, but sadly, you've chosen a Mustang that very few ever liked.