Mobile Lumber Rack

Designing and making a mobile lumber rack As I (Jonathan) delved more seriously into wood work over the last year, it became quite clear that I needed a lumber rack. Increasing volumes of wood have been stacking up in one of the garden sheds, on top of eski, camping gear and the like—not a very practical arrangement for an ongoing hobby. It was time to make a lumber rack. Requirements As we are renting, my lumber rack would have to be stand-alone (as opposed to attaching to exiting walls/ceilings). It would need to fit through the door of said garden shed (so not too high), not be very deep (since the biggest, non-negotiable space-taker in that shed is a ride-on mower), and of course not be too wide for the available shed space. Obviously, it would need a good number of shelves for lumber, and also have space for wider sheets of ply or the like. It would be preferable for it to be mobile, so it could be rolled out from the wall to access the back of it (where the wider sheet...