If you want a plain i3 standard geared extruder here it is, this extruder is based in Ch1to's model that is based in a Wade's extruder with the motor and gears rotated, I made the CAD model from scratch however I did follow his extruder, basically is Ch1tos work with minor improvements, I revise the geometry there where some minor errors for the screws and concentricity of the motor also I removed the need to use a M8 bar for the idler instead it uses a bushing and M3 screw and nut, there was a nut that lived on the inside of the idler removed it for a more conventional outside nut, added zip tie points for wiring, removed the mounting point for the duct in the front since the SunBurn has it's own duct and all my extruders are made with the SunBurn hotend in mind, small changes to make it a bit more aesthetically pleasing since I found the original too "Square" some other small changes that I do not remember.
You are going to need the X-carriage from my website http://infill3d.com/24-i3redux since you need to have a notch to accommodate the large gear, there is 2 available either with 3 or 4 linear bearings.
All in is a standard i3 3mm geared extruder that is very reliable based in a Wade's/Ch1to extruder.
3x 608ZZ Bearings
2x M4X50 (Idler to extruder)
2x M4 Nuts (Idler to extruder)
2x M4 Washers (Idler to extruder)
2x 1/4 x 1/2 x .035 (6.350 x 12.7 x .889mm) Utility Comp Springs
4x M3X25 (idler, clamp)
4x M3X20 (X-carriage)
9x M3 Nuts (idler, clamp, small gear, x-carriage)
1x M3X6 set screw (small gear)
1x Hobbed bolt (distances between the center of the groove and the base of the head should be 25mm +/-)
1x M8 Nyloc nut (hobbed bolt)
7x M8 Washers (hobbed bolt)