5.6.2019:
As requested by shbatm i uploaded the (kinda messy) Solidworks file of the carriage!

Update Time! (BOM, a better description and a nifty cable anchor on the carriage)

The new version has a spot to attach your cables to!

BOM:
1x E3D V6 (Trianglelab)
1x Bmg Extruder (Trianglelab)
1x "Pancake" Nema 17 (Trianglelab)
12x M4x12mm (original Anet ones)
9x M3 Nut
8x M3x20mm (Fans and Beltholder)
3x M3x38~mm (Extruder through carriage into Nema)
1x M3x8mm ( for the Anet cable clamps)

Beware!
If you are using clamps of any sort to attach a buildplate onto your heatbed, the fanducts WILL collide with them...use 3M Adhesive instead :)

This Carriage is made for the old Anet X-Rod spacing of 45mm!
But the lower bearing can be adjusted up and down, so it should fit from 44 to 46 mm spacing!
If you don't want to use two radial fans for a particular print you can just plug the port of the unused one with the "Düse anschluss test1.stl

If you don't use printed bearing blocks (wich aren't as bulky as than the stock ones) you will have to file the top side of the lower bearing down so the belt holder will fit.
I used the belt holder from this carriage https://www.thingiverse.com/thing:2848916
Besides the old screws and nuts you will need some additional M3 hardware.

The whole carriage weights about 400g fully assembled, which is a nice saving from the ~560g of the stock Anet A8 Hotend (botrh without bearings and bearing blocks)

Left to do:
Maybe improving the fanducts