Sorry Dude but I have no idea as to how much it would cost you, but I bet it would be pretty damn expensive. It would probably be hard even for a shop to estimate a close price.
Also, if you did decide to get this done, make sure you go to a shop that knows there shit. You dont want them to screw up when cutting your frame.
Without some pics of the frame, I cant tell you if you would need to modify the doors. You probably would tho, which would be diffucult as you probably would have to custom make the hinges, etc....
I suggest calling a shop near ya, and tell them what you want. I think you might scream when you hear the estimate tho
--Rich