I dislike the flat wood backplates that our machines have, and feel like 3DP parts could be stiffer, and more visually pleasing.
I also wanted to try out optimization with Altair Inspire, as I have a demo of it currently. I modeled over optimization, then finished engineered details.
And thus, this "ribcage" for the Z-axis of our machines.

You'll have to trim the underside blocks to fit the holes in your plywood, as I modeled them oversize. You'll see in my installation that I broke an arm - it's not a perfect thing but it's GREATLY improved over stock. The Z axis is rock-solid now.

Works best with RC-Lohas stainless stiffeners and the spacer blocks for them here on Thingiverse (http://www.thingiverse.com/thing:770902)

Designed for a 5mm thick plate of glass, but you can move the mech-stop-block down by chopping away at it. It might be within spring-space of being able to take a stock build plate. YMMV.