I have had an old flat receiver mount steel mesh cargo carrier in the garage for a long time and have been thinking about how to build or transform it in to more storage and a slide-out bike rack. I borrowed a few ideas I've seen here and finally got it done. The problem I have with most I've seen is the inability to open the rear doors, so I thought out how to build a slide out one similar to TmTm's rack, but with a bulletproof 3 point mount I could add a lot of weight to. The stock 1 tube rack is rated for 500 lbs but I wanted a wobble free rack I could really weigh down if needed. My van's receiver hitch is a 1000/10,000 model so no worries there.
I started by adding a box of made of angle iron to my present hitch rack
Then i bought 2 5' receiver tubes and 2 15"ish larger tubes to weld on the outside of my van's receiver hitch. I wanted to make it lockable so I figured the easiest thing to do would be to weld the side tubes on flush with the center tube and just use the original pin/lock setup I've always used. It's a little tight to get to, but works great, without having to crawl under van. Also, I can take the rack off completely by removing the pin and sliding it out with a second set of hands.
Next I added my bike racks to the top and finished out the rear with a flat piece of angle across. Plenty strong
Photo above is locked to vehicle and below rack slid all the way out with clearance for doors
Surprisingly it doesn't sag the van even fully loaded. It doesn't drive like it has a lot of weight on it, and it doesn't rattle at all
I road tested it and took the first trip out this Spring up to Big South Fork NRRA, a beautiful place. Got rained on the entire trip but still had a good time. I loaded the rack down about as heavy as I ever will with firewood and bikes and had no problems. I still plan to add a trailer light set/tag holder to the rear since I designed the rack to just be left there. I'm also going to add a backup camera soon so I don't back it into things. I'm pretty long now with this rack on the extended van. If it looks like the rack sags a bit, remember it uses the factory center tube with 2 added on the outside, so that's just the way my hitch is built. It's almost like the angle is designed for the van to sit up higher in the back, which would make the receiver more level, but my van doesn't sag, not really even with this rack on and loaded. Not sure why the factory hitch isn't more level, but of course I never noticed it until I built this huge rack.
Big South Fork at the Twin Arches (nothing to do with the rack, but a great first trip out this Spring)