my dad has a shopbot.
i can get you all this info around tomorrow or so the next time i go home.
what i know for now:
Angle is i believe 1.5x1.5x3/16? the top surface the bearings ride on has been milled/surfaced/or somehow ground.
the main rails of the gantry are 3x3 box i believe.
Pretty sure all the steppers are the same.
the vee bearings are same as these
item number 3672K11 at www.mcmaster.com
rack and pinion not sure but can find out.