This thing is small! You can make this using a few laser cut parts and your MK4 extruder hardware. There are a few tweaks I need to make, but it's closer to the final design. For more information see my blog post http://charlespax.wordpress.com/2009/10/30/paxtruder-0-2 .Derivatives Paxtruder-0.4 http://www.thingiverse.com/thing:1332 Drop in paxtruder http://www.thingiverse.com/thing:1351 Paxtruder Mount http://www.thingiverse.com/thing:1341Subversion http://svn.makerbot.com/users/charles/paxtruder/