I would imagine that the next constraint in the size would come from the supply chain, so you'd probably end up seeing panels that are 4'x8' if human liftable weight wasn't a consideration.
Perhaps the next size up would be the interior dimensions of a cargo container so they could slide in/out like sticks of gum.
Perhaps the next size up would be the interior dimensions of a cargo container so they could slide in/out like sticks of gum.