Full crossbracing for Prusa simplified Mendel

AKA sildenafil for Prusa Mendel, part of the mythic quest for less vibrations and bending, a more rigid frame that can work with more tensioned belts.

Also check: Y motor mount torsion box for Prusa simplified Mendel http://www.thingiverse.com/thing:11017
Smooth rod / shaft collar from a drilled out M8 nut http://www.thingiverse.com/thing:11068

Selis Mendel features a plywood or acrylic plate there, Prusa Mendel has nothing. I am too lazy to cut plywood right now, so here it is.

Inspi