Recommend a 1.75mm open source cold end?

Hi all,

I currently have the August 2013 version of the 1.75mm Mix G1 extruder that I want a new cold end for: [forum.mixshop.com]
I can't complain about the hot end as it easily lasts through a 5hr PLA print without jamming, but the COLD end / extruder has a few issues I'd like to be without:
- The fans mounted on the sides limit my X-axis print area because they hit the Z bars
- It is hard to load: I actually have to remove 2 nuts and a screw to load new filament because that takes less time than snaking the filament through with the assembly closed
- I'm right at the limit of my extruder motor controller - my Pololu A4983 driver is borderline overheating, and any less current or tension will cause extruder skips. The hobbed bolt and the bearing are clean, and the borderline overheating is with a heat sink and fan blowing over my RAMPS.

The Mix G1 extruder mounts to a horizontal X axis with the 8mm bars 50mm apart, but I'm confident I can modify something.

I'd like to try to modify myself (hence the open source requirement) a smaller extruder to attach to the same hot end, but I'm not too familiar with cold end designs. Do you have any recommendations for cold ends on 1.75mm filament that are easy to load and have space for a fan? Also I don't have any bench tools other than my 3D printer, so if possible I'd like most of the parts to be preassmbled, printable, or possible to hack together with a hand drill and rotary tool.

Thanks!

Most people use a Wade-type extruder, like this: [www.thingiverse.com] . It is quite large though. You could also take a look at RepRapPro's mini extruder, shown here: [reprap.org]

Thanks!

I'm not quite ready to try a Bowden extruder, especially since my printer can't have anything load bearing at the top of its Z rods, and putting that kind of extruder on the X axis would just be silly.

Hmm I was under the impression that the Greg/Wade extruders were all for 3mm filament... Silly Wiki and its redirects
That allows me way more options than I thought I had.

Would it be worth doing a Vertical X mod [reprap.org] ?
The Mix G1's Z holders are already 65mm tall anyway, so I won't notice the added height with Vertical X. The advantage (at least what I'm thinking) is that I can put the PLA printing fans in the front of the extruder to not take up X axis printing space. Right now I don't have that option as the X linear bearings (and their holders) are in the way.