Looking at the mainframe assembly guide, I see:
6 x 2" diameter PVC standoffs
Looking at the BOM, I don't see these directly listed. Is the intention that they're fabricated out of:
PVC sheet, white, 1/2" thick, 24" x 96"
These standoffs are placed at the bottom of the PFC. I guess they are supposed to be a part of a set including screws. I don't think they are functionally critical, you just want to be able to have some air underneath the PFC.PVC is something that I would want to avoid as much as possible anyway... so just have something that raises your PFC from the ground a couple of millimeters, that will do.Look at @silversson diary, he put some wheels on it (as I will too..) http://forum.openag.media.mit.edu/t/build-diary-of-jussis-food-computer/33/12?u=peperoni
I could not find any store that sold standoffs and just cut out them from the PVC sheet you mentioned using a 2" diameter hole drill bit. They do however sell the 2" pads to put on the bottom at local hardware stores.