Clev,
I have a 2015 F350 CCLB SRW with the factory hitch and I tow a 15000 lb 5th wheel trailer. When traveling I need access to the bed and like you really didn't want a large hitch taking up most of the bed.
There were 2 options we looked at very hard, one was the
Andersen Ultimate Hitch we chose not to go through this route because I didn't want to install this every time we hooked/unhooked the trailer. Below is a link.
Aluminum Ultimate 5th Wheel Connection 2
The second choice was the
Reese Goose Box which is an approved kingpin replacement of the frame manufacturer.
We ultimately went with this for a couple of reasons the first being it has a built in suspension system and the second the simplicity of hooking up.
All we have to do is put the GN ball in the truck and back up and hook up, when we get where we're going the only thing in the bed is the ball and it comes out in a few seconds easily. We've had no issues with it except replacing a faulty valve core and will highly recommend the product. Here is a link.
Reese - Goose Box