It would probably be cheaper to simply buy the muffler that you want, and take it to a shop that can mandrel-bend exhaust pipe (keeps the same inside diameter when making a bend).
Jim Carter truck parts has factory style mufflers if that is what you want, or you can use an off-the-shelf brand if you want a whisper-quiet motor.
I have a factory style muffler from JC on my truck and tailpipe that dumps out under the rear bumper in the stock location. It's not the quietest, but sounds great in my opinion.
