This is a great design, and I am currently building one (will post pics soon). My only concern is, is anyone else finding some parts a bit too tight ? I've had to re-design the locks which sit on top of the roller blocks, because when I clamp them with the conduit installed, it puts way too much force on the plastic loop which holds down the other end of the lock (potentially breaking it off). I have similar problems with the corner mounts and the locks that sit on top of those, it's like the 'hole' the conduit fits in is too small (I measured it with calipers it's about 24.2mm). I'm using 25mm dia. 1mm chrome plated steel tube (think towel rails). Works a treat.
None of my issues can't be solved however, and it's coming together really well. The conduit slides perfectly through the roller bearings once everything is fitted, with no slack. This tells me that everything is printing dimensionally accurate, so my problems are a bit of a mystery.
Brilliant work on the design though, and I'll let you know how it goes.