Having built three Dave Platt 81 inch Mustangs here is how I would go about it if I were going to make a kit. First, a fiberglass fuse complete with vertical fin would be a huge advantage. The Mustang fuse has some pecularities when it comes to shape that are hard to capture unless you have really great documentation. Best to put the R&D into the plug and not let the customer have to worry about it. A particular area to be careful of is, of course, the nose. Most people don't realize a Mustang fuse, when viewed from the top, is constant width from about the trailling edge of the wing to just in front of the exhaust stacks. It then pinches in rather dramatically to match up with the spinner. It is NOT a nice flowing curve into the spinner. It is much easier to incorporate a full cockpit and/or some type of internal exhaust routing within a glass fuse. Just make sure you do your homework while creating the plug! Same goes for the panel lines. If you're going to put them on make sure they are accurate and let people know which drawings you used for documentation purposes.

For the wing I would use CNC cut foam except for the retract area. Everthing in front of the main spar from gear to gear would be built up to incorporate the retract units and make for a scale appearing wheel well. On anything 85 inches or less I would not make plug in wings as there is no good place to hide the break, IMHO. We do want this to be the most scale Mustang available right? The horizontal stab and elevators can be CNC cut foam also. However, they need to be cut seperately as the elevators do not match the airfoil of the horizontal stab at all. They are a bit fatter and somewhat teardrop shaped. For landing gear I would see about getting Sierra Precision to do the retracts and struts. They did the struts for my Platt airplanes and they are beautiful. This is the kit I would like see made but that's just my .02 cents.