there is several threads on just this subject here at RCU.
there are numerous creative ways for a plane rack I am sure there will be a bunch of good ideas coming soon.
I also have a short bed in my Toyota Tacoma I use a folded tarp in the bed,to set my fuselage's on, and a old heavy blanket for padding for the wing's to lay on over the top.
a rack won't work for my planes most of my wings are too long for my bed,and have to be at a angle to fit so the blanket works well and holds the wings in place so there not swinging around getting a rash.