Do you realize that 747's and major bridges are built with torsion boxes?

Irrelevant, but long ago I actually designed and built a bridge based
on the torsion design. This was done out of balsa using crazy glue.
At the competition, not a single stick fractured but the bridge
twisted and snapped at the glue joints :-/

I improperly pictured the proposed solution when I replied. Now that
I better understand the cross-sectional design, I think it's an
excellent idea. So essentially, I take two sheets of (any particular
wood type?) 3/4" plywood, cut out U shapes from each sheet to form the
front and the rear cross section. Then lay bending plywood on top and
bottom? What kind of load will this design be able to support with
only a 6"-wide cross section? Will the corner in the bend be strong
enough and not tear apart without reinforcement?

What are my options for joining the cross-sections together? I will
need to center three 50lbs (each) components inside the table top.
Each will be about L15"xW15" and need to be placed/removed from top of
table. This means that whatever flooring I use for the table top
span, will need to be sturdy.