Just posted this in a similar thread, this deserves to be here too... I notice not many people post pics here, but here is a pic of my plywood bed, and a link to the photos I took on the day we did the install.
http://www.grossepointegothic.com/71stepside/woodbed/ [img]
http://www.grossepointegothic.com/71stepside/woodbed/image/pict4233.jpg[/img]
It was a good $30 solution when I had alot of other more important work to do on it, but I needed something back there. It was completed in one afternoon and has been in there for six months. It's the most expensive 3/4 wood they had available and it looks great to me. Most beds wouldn't need the border like I did on mine either, my bed is all ramshackled so it was a little to wide. I'll probably still do plywood when I redo the bed, along with a wood toolbox that will also cover the gas tank that is going to be put back there. I think the stain looks great.