This turned out very well. A ATV hitch haul rack,my bike rack and parts from a Thule bike rack added for height so bike clears cargo area.Rack fits inside Casita tail lights for clear view. Built with heavy 2" square tubing and braced. You could pull stumps out or hang a deer from this. My Hitch on Casita is welded frame to frame and does not touch the bumper so it's rock solid.
rack pics (http://good-times.webshots.com/album/562783161lePrgh)
(http://inlinethumb23.webshots.com/40534/2676847660043540764S425x425Q85.jpg)
It looks like you can haul a lot of stuff back there. I thought about doing something similar for the kids bikes on the back of the pop up. I changed my mind when I came out of a gas station that had a steep driveway. The back bumper got caught on the steep grade and had the tires off the ground for a second. How much worse would it have been with a hitch mounted under the bumper. Be careful coming off of steep grades onto flat ground.
Ride height was part of the build process. The receiver is a couple inches higher than the bumper on my Utah and I never once drug it in five years of use, even off road. Also the base bike rack I have used for years and had no clearance issues.
(http://inlinethumb56.webshots.com/21367/2539550660043540764S425x425Q85.jpg)
It looks like you are higher off the ground than my Niagra. It would be nice for carrying some fire wood. The storage box on mine is more than large enough for my gear. Nice work.
The first picture looks like you have some lights on it. It may just be a reflection. I have reflection tape on my back bumper. My 13 yr old son keeps trying to talk me into putting some neon under the camper. He wants it to look like it is floating down the road. He also thinks it would be easier to find when coming back from his shower at night.
Just DOT reflective tape on back of rack but I did do the neon light thing under steps and yes it looks like it just landed at night.
(http://inlinethumb02.webshots.com/38401/2368467380043540764S425x425Q85.jpg)