Here is what I just finished up (needs paint still). I modified my BossHog tray with a top framework and platform. This effectively doubles the volume of the carrier. I bolted on a stair mount to accept the standard set of stairs I use with the camper. I kept all of this simple and modular--the frame bolts onto to carrier, the platform is held on with pins, and weatherproofing is simply a tarp bungeed on. The height of the platform was governed by the height of my Honda generator. With the platform on I have about an inch clearance for the camper door to swing. I'll post up a photo of it on the truck when I put the camper on in a few weeks.