Rigid Back Plate for Narrow X-Carriage

This backplate part adds a lot of rigidity for X-Carriage design of EkkuZakku https://www.thingiverse.com/thing:2563543 which is the best X-Cartrige for my opinion by few points at once:
- it allows full X and Z movement because it is more compact;
- it has very convenient and reliable belt tensioner;
- it is lighter. The lighter - the higher max speed. Well, I am considering to make a fan and duct either to be easily removable or to be small and light, because I print almost only ABS+ which