Which one are you referring to Sven7?
Edit: the M-1000 appears to be in a French museum?
Here's another car that may have been on this thread before - the 1956 Citroen C10 Coccinelle:
Looking at the drawing again, I think the car was built longer (in the rear in particular) than the drawing shows. The tail is already a bit steep, so the drawing was probably an early sketch. And more fun with packaging and how to best utilize the interior volume. Luckily, the engine on the 2CV is pretty compact and fits under the front seats.