Parametric bracing frame vertex

The inherent floppiness of the Prusa frame annoys everyone. Here's my attempt at fixing it. This thing keeps the same rod spacing, though you will gain a little Z height and Y travel at the expense of some X clearance, if the nuts are right at the end of your rods.

Also, this thing can produce accurate copies of the Huxley vertex (by editing the scad file), which is not available in openscad format, I believe. Which also inspired me to make this, as I think they look cool.

Detailed description
I've been wanting to stiffen up the Prusa frame for a while, as my intention is to have a removable carriage for light milling http://www.thingiverse.com/thing:11535 . This thread http://forums.reprap.org/read.php?151,112816 (you'll need to manually copy and paste the whole address, thingiverse's new style can't cope) got me thinking about how to stiffen up the Prusa frame. One thing I never understood is why the triangular section of the frame gets the widest part of the vertex, despite a