I built a 3D printer in 2011. I started with a rough kit and had to build everything. Once I got a first version working, I updated most of the part (the blue parts) with linear roller bearing for the rails, a chain to maintain cables, a holder for the plastic, a case for the electronic with a fan, and several other parts to hold things in place. See photos and videos below.
It was a lot of fun! I notably printed the first part of the Poppy project with this 3D printer back in early 2012.