Yea, I hate to say it too, but a cab swap is the only way its going to be 100% again. Even if your body shop guy TRIES to make everything right again it wont be as good as a factory cab swapped onto your frame. And yea, might aswell upgrade to a 3rd door while your at it.
Hopefully your mechanic friend sticks to his word and isn't just saying things to make you feel better and backs out later when he sees how much time and money its going to take. Not to be a downer but I would get something in writing with that cop as a witness, that your mechanic will see the project through to the end. If he is against that idea, then he wasn't planning on ever fixing it in the first place.