Grendel mags?

[Rambozo]

I think a "proper" double stack is necessary for two reasons:

(1) to keep magazine length to a minimum; and (2) to correctly align the top rounds with the barrel feed ramps.

What you propose would result in a significantly longer and heavier magazine, and because of the reduced stack width, it might not permit reliable chambering.

I doubt that it would require a significant shift in the stack. Still, it isn't as if feed lip, follower, or mag geometry can't be also tailored to fit the different stack width.