>Literately about a week ago I pulled out my 1/72 Tamiya PR IV and was pondering how I could stretch out the wings. The taper of the wing has stopped me a this point. I also thought about cutting off the wing off right at the engine nacelle and putting a new wing on.<
The U-2 wing outboard of the....gas-tank-looking projection...should do, but the wing is very thin. If you can find the 4-engined DH Heron (1/72) kit (fairly rare, I'm afraid), that at least has "DeHavilland" wings, but longer, with minimal hacking of nacelles. Another source may be 1/144 4-engined bomber wings. The 1/144 B-29 looks good, but you would have to eliminate the engines somehow. I don't know about B-24 wing/engine interfaces. But there ARE suitable wings out there!!
Here's a photo of a U-2 wing adapted to a 1/100 He-111 fuselage (and, of course, numerous other "modifications") for a high-altitude jetstream-riding fighter for Japan (ex-German He-121). The general shape of the fuselage and tailplanes is reminiscent of the Mossie. Your twin-engine nacelles might go where the...gas-tank-looking projections...are!
>So I should also try to find the OOP Matchbox which has the longer nacelles.<
Since I used a combo of P-82 and Lancaster for my "Flounder" nacelles, I am SURE I have the unused Matchbox Mossie nacelles somewhere, and you would be welcome to them if you are serious about your project.