I'm pretty sure that the process would be to heavy for the strength it
would provide, unless it were modified to provide several very thin
crossing layers, all of which woul have to be tightly glued to each other

I'm no expert in (or any field) but several people have mentioned about the
lack of strength a single layer plywood would have and you'd need several
layers (ad various angles) etc etc. Yet the most common new "core"
constructions uses styrofoam for a core, I'd think the plywood at almost
any thickness would be stronger. The reason for use the plywood would be for
the looks (at least that's my guess).
John