Great video of Printrbot speed build by youtube user HammerFET. In ten minutes you will see in detail how his Printrbot is build from scratch to fully operational. It has xbox power supply and few other customized parts.
Video description is:
Video description is:
Printrbot featuring my minimal direct drive extruder and xbox power supply!
Whosawhatsis' MK7 replacement: http://www.thingiverse.com/thing:15718
My extruder carriage: http://www.thingiverse.com/thing:29146
Toggle switch holder: http://www.thingiverse.com/thing:29497
Two part printrbot base for easy printing: http://www.thingiverse.com/thing:26266