Mopar used to make a mid length header for the magnum V8's. Maybe you could get in
touch with someone in the parts dept (yeah I know, the stealership) to see if they still
offer them. I heard it was actually a good piece.

 

Unfortunately the only company that sells long tubes is pace setter. And that's about 1 step up from summit brand parts. Now there are places that will custom build you some awesome quality long tubes, but it's gonna cost you.