It looks that 91X91 PCB dimension is a bit strange. 90X90 seems more appropriate and does not reduce really the real estate of the board. PCB Calculations are easier that way.
A small reposition on the 40 pin Raspberry connector made so the center of the connector to be aligned with the center of the mounting holes. The same way things done on the Raspberry Pi .
It is very crucial on this redesign to fix PCB outlet, mounting holes and Raspberry PI 40 long pin connector that connects various boards together.
PCB is still open for suggestions.
We are talking now with a very old and established company in electronic design.
Hopping that discussion will produce an even better M10CUBE design for the community.
A PDF and a step file will help you to see the actual proposition
We are open to discussions and criticism.