Canon could make showoff camera powershot G9 sized R ILC with medium format sensor
good spare camera
Now if LCD is away ,back wall and sensor together could be 0,5cm thick +2cm flange distance 2,5cm body thickness.
28 mm pancace lense would be like 3cm? ,now lens mount could have in retreating screw construction what makes it 1cm shorter when power off so over all thickness 4,5cm.
Wievfinder should be placed left corner then nose would be free left side of camera and no back construction needed.
Look sony full frame camera and you see how sensor is stuffed inside mount not any space wasted .
If canon stuffs sensor like sony it would be 4cm x 2,9cm sensor ,so medium format
If only single shot camera no needing space taking computer stuff so much.