Some of the original printed printer part.

THE Printrbot.

http://www.thingiverse.com/thing:16990
Created by abdrumm Feb 4, 2012
This is the real deal, no derivatives here. These are the real Printrbot in it's current version.

A pulley for use with XL belts

http://www.thingiverse.com/thing:6822
Created by Jaydmdigital Created on Mar 3, 2011
A XL 10T pulley with a locking setscrew.

Parametric Herringbone Gear Set for Greg's Accessible Wades

http://www.thingiverse.com/thing:10707
Created triffid_hunter Aug 13, 2011

My modified or ported printrbot parts.

This section is redundant because you can just view my thingy-verse page.

http://www.thingiverse.com/eddiema

pb-Y-BarEnds-mod

http://www.thingiverse.com/thing:22357
Modified Y bat end
It is similar to a thing by buckyball but has the hole in a different place.
The hole is where I think it needs to be for my printrbot - this may vary from bot to bot

pb_z_end_stop

http://www.thingiverse.com/thing:22358
This is a port of buckyball's ZEST to sketchup.
This is a mod brooke made for early printrbot kits. New kits have this incorperated into the base already.
It is for holding the Z axis limit switch.

L10t_pulley-D26.stl

XL10t_pulley-D26
http://www.thingiverse.com/thing:22530
XL10t_pulley increased to 26mm around the screw hole. The original looks OK but they have been spiltting near the screw.
Based on thingiverse.com/thing:6822 but redrawn in sketchup.