I was looking for a FLEX direct extruder because it is easier change filament, but couldn't get any for my MK8 feed gear (9mm diam ext x 5mm diam int), so I designed my own. There are three printed parts: separator, body and idler. You will find in the explosion file all the other parts you will need.
The body has a funnel that will help pass the filament from side to side when the through holes are misaligned while pressing the extruder
UPGRADE: I added a new separator with support for fixation. Although this one is a bit wider that the original, the listed M3x12 threads are still enough for motor fixation
Don't forget share the results when you make it!