I'm aware of such a device which fired the .22LR (barrel protruding between middle and ring fingers, fired by squeezing a trigger mechanism with the closed hand, made in the earlier half of the 20th century in Chicago, IIRC), but not any real pistol which fires a 9mm-or-better round.
The P7's bore axis is relatively lower than any other combat pistol (in 9mm or larger caliber) extant.
Muzzle flip is reduced by lowering the bore axis relative to the axis of rotation for the weapon until, where they coincide, there's a straight-backward push. Trouble is, it's hard to design other features (reasonable overall weapon size, reasonable weapon shape, reasonable ammunition capacity, visible ights, etc.) to accomodate this constraint, especially for a handgun, less so for a rifle or other shoulder-fired ordnance.
Best.