Cheap Engine/trans dolly

I like the ingenuity I'm seeing here. I am going to have to pull the entire drive train and rear end to do some frame/body repairs. I think I want to drop the engine/trans/K-member out from underneath in one piece and store it that way. I'm going to have to rent a storage room because I've run out of room at the inn and my wife's van has to come into the garage for the winter time. I've got two sets of two caster assemblies mounted to 3'x4"x3/4" thick steel bar to build off of. Does anyone have a drawing with dimensions for the support points? I assume you pick up the four mounting points and then an extension under the trans mount? I can measure, but I'm lazy and if that's already been figured out....
I'd like to build one at some point like dragonsteel did too. On mine, the only thing I measured was the 8.5 inches between the 2x6's for the oil pan rails to rest on which wouldn't bee needed for a k-frame up dolly. The rest I eyeballed and mad a mark with my thumbnail where to cut the wood. The pics on mine look like the rear trans support is on the wood crossrail, but it's not, the trans pan is resting on the 2x2's. It doesn't seem like there's a lot of weight on it there, so I think it's fine.