While they're no longer operating, they kept their page up, so all the documentation is still there. The Melzi-based Tricolor is further down the Documentation page, under Discontinued Machines. The direct link is [
reprappro.com] . If you go through the sections of the instructions for what hasn't been assembled yet, the parts are listed.
The master-and-slave Melzi arrangement had its share of quirks. I was in the process of almost getting it acceptably reliable when the bed terminal on the master melted down on me for the second time. RAMPS won't natively support the third extruder, from my understanding. Personally, I'm partial to the Duet/Duex4 bundle, which will, with a Duet 0.8.5, support up to six extruders, but it is considerably more expensive.