This is my take on the bowdens mount for dual extruding on the MakerGear Prusa (along with my previous upgrade on the Z-Axis).I've taken the 2 Extruder Mod by dob71 and redesigned the hotend mount for easier assembly. I have also resized everything to fit 1.75 filament.The X-Carriage has a wider opening to give enough room for both hotends.Just as a note, I have been using this setup for about 2 months now (as of Aug 02, 2012). I've mostly used it as a single extruder because I haven't gotten a concrete way of generating dual-extrusion gcode yet (working on it). The print quality isn't perfect, but it isn't bad either (in fact, the pictures you see are all from a second set printed while using my first set). I ended up using a slow retraction of 10mm to remove the blobbing and nozzle drip.INSTRUCTIONSThe two shoulder mounts go on the top of the printer on both ends of the two top horizontal rods, they should replace the two bar clamps that hold the top of the Z-axis smooth rods. Take the filament tubes and screw an M5 nut to the ends of each tube. One end of each tube goes to the shoulders and the other ends go to the hotend joint, each should have an M5 nut trap that is used to hold the tube in place. The two hotends should slide into the hotend mount and through the opening of the X-Carriage. The hotend joint should fit over the tops of the two hotends and they should all screw together with two M6 bolts.As for generating gcode for dual extrusion, I have been working on splicing software for this. It allows you to import multiple gcode files, assign your intended extruder to each one, and output a final spliced gcode file that will print your final product! It is still in beta stages right now. Check out some screenshots of the latest splicer here: https://bitbucket.org/Lochemage/lochegsplicer/wiki/Screenshots. You can also download the latest windows installer here: https://bitbucket.org/Lochemage/lochegsplicer/downloads. Enjoy!