I remember that picture too... but haven't searched for it yet. All you'd need to do (as long as this is a temporary cart being used since wood will warp, twist and sag from humidity and age over time)... is make a rectangular cart with a caster bolted under each corner. Use the rocker panels as a guide for your dimensions since the cart will sit under the rockers to support the shell. You want the cart as long and wide as possible and convenient, to provide the most stability and balance.
Here's a picture of a wooden body cart that I used temporariy for my '69 coupe. Again, if it's temporary, wood is fine --short term. But anything longer than that-- go metal.:yes: Trust me. I spent around $300 for the metal and hardware on my metal cart at the time, and have no regrets at all... It's one of the best tools you'll own.