K8400 with over head extruder

I’m currently upgrading my K8400 to be able to print soft filament like Ninjaflex and to do that I need the extruder to be as close to the print head as possible so I have found this thingiverse.com/thing:1999666 that I intend to use but some questions come to mind.
I’m not so fond of increasing the wieght of the print head by several hundred grams adding the Nema17 motor so the question is are there smaller stepper motors with the same screw fixing pattern and if so would a smaller motor be enough ?
I imagine the reason for Velleman to supply the kit with four Nema 17 motors is for simplicity, not for the actuall need of four motors with the same torque.

Could you make any picture of that? It is exactly what I thought about. This tube could be shorter 20 cm with extruder mounted on upper corner.