There are so many different designs for building bed platforms but this definitely seems to be the most practical. Main reason I'm building is because I've got two yellow labs that go everywhere with me and having the space underneath the platform is going to be perfect. I wish I could get another inch or two of clearance under the platform but I'm pretty much right at the perfect height for the dogs to have enough room to move around.
I got free 3/4" plywood from work so I cut the cross beams in 7" widths from the the sheets of plywood. This is as far as I've gotten so far, we ran out of daylight, and beer. But I'm going to cut my two sheets when I get off work tonight. I've got the grey outdoor carpet from Home Depot
that I'll glue and staple down after that. I'm glad that someone mentioned not building the length out all the way to the tailgate to prevent water getting on the platform. I was definitely about to build out from end to end.
I'll put up some pictures once I'm through, I'm sure it won't be the prettiest thing in the world but the more pictures the better I think. I'm also considering attaching a flip up door and attaching a lock. So even when it's unlocked I can remove it easily but having it locked would at least slow down anyone trying to get in there. Just a thought.