No, I am sorry we do not have what you're asking for and as far as an aftermarket part goes I do not know of anything like that you can purchase. You either need a set of rails to attach a 5th wheel hitch, some kind of gooseneck platform to insert one like item # BWRVK3050, or a factory puck system which is the closest to what you are describing.
What your asking for sounds like a custom job and you'll need to locate a fabricator. If you change your mind please feel free to email me back... view full answer...