Ok a bit late in the game but my Son had some spare metalwork so I fired up the Prusa Mendel and built this bad boy. I'm already enjoying considerably more resolution and much more stable layer positioning. Impatient as always I'm finding out calibration problems the hard way.
As already mentioned by another contributor the top bars are about 10mm too short for this iteration however the drawing does show the Z bar supports hanging out by 5mm. No big deal but I found out the hard way. I was making a bit of an assumption.
Many thaks for this wonderful project it is so much more ridged than the old 8mm threaded rod.