This is my adaptation of the E3D Hemera extruder on Anycubic I3 Mega as direct drive unit. There are two main components required to be (relatively easy) printed. Additionally, two tensioners, a bracket for the drag chain and a cover for the PCB board are all 30 minutes very simple prints.
I have used an E3D Volcano heating block and Igus RJ4JP-01-08 polymer bearings - but these are optional - normal LMU8 or LM8UU bearings and any other E3D (type) block can be used.

• EDIT 1: Added for E3D V6 heating block a dedicated fairing for the 5015 blower.

• FINAL EDIT:
  The last minor design evolution and refinements, as well as the complete CAD data, 2d drawing and hi-res pictures are saved in:
  https://github.com/Sergiu-I/Ai3M---FoX-50mm-ZX-Axis/tree/CAD-Files
  If opening a step file and saving the required models as STL files sounds unfamiliar or is too much trouble, the included models are very good too - they are fully tested and satisfactory working on several machines.

The assembly is simple and straightforward. Only 6 screws M3 are needed: 2xM3x16mm for the 5015 turbine blower duct attachment, 2xM3x20mm + 2xM3x35mm for X-belt tension system, all with washers and nuts (M3 of course). The images show all the required information.

Installation of the Hemera unit, 4 screws M3x8 + washers, included in the Hemera kit, clearly described here:
https://e3d-online.dozuki.com/c/Hemera_Assembly_Guides
or
https://e3d-online.zendesk.com/hc/en-us/sections/360004096837-Hemera-Assembly-Guides

The weight impact is minimal versus the original AI3M metal solution, considering the major Bowden to direct drive modification. I could keep all the values for printing speed and accelerations as in the Bowden configuration. Most of the direct drive solutions I have seen look way more massive and heavier - I cannot really quantify the differences because I could not find any given weight information for these solutions.

The design uses and re-mixed geometry from:
https://www.thingiverse.com/thing:3537449
(X-belt tension system, cable chain attachment, PCB holder) with small modifications and improvements - thanks again for these excellent solutions.

The cable chain from images can be bought or printed:
https://www.thingiverse.com/thing:3668667

Anycubic I3M

No

Yes

0.2

25

I have used ABS in order to get the nice, shinny "casting" surface look using the acetone vapours smoothing process. As a bonus, the Hemera symbols kept in the same vapour container have become sticky and flexible, and I could wrap and stick the large symbol on the carriage front-top curved surface and just stick the small one on the cooler duct fin.
But other printing materials (PLA, PETG, ASA) most likely will be functionally OK.

Components saved in the optimal 3d printing position.

EDIT 1: Supports should be enabled when printing the main components. I highly recommend the Prusa Slicer 2.0 with user defined enforced supports.