Next project converting rear seat to bed

[Hit it like a champ]

I have been thinking bed sides. I was looking at some aftermarket bed conversions with hinges that fold out. I was thinking more on the lines of a one piece bed side so it looks like a bed all the time. Then a hinged tailgate that will fold in when the seat is up. I have a large sheet af 1/4’’ aluminum that has been setting in my garage attic for over 10 years i think i can use it or maybe 1/8’’ diamond plate steel. Anyone have any ideas or picks of how they did this. Found this pic. The second picture is what i would like to do. Can i buy those sides without buying the whole seat.