Similar to the CFL. Offense lines up per usual with the ball. Defense is pushed back 1 or 1.5 yards (2 is probably excessive) and can enter the zone the second ball is snapped.

There are some side effects (goodbye tush push) but it drastically reduces helmet contact for those 8-10 players every down.

And indeed, disallowing brace against ground is all you'd need to get the standing result.

I think the league would be weirdly resistant to the standing rule. So much of technique is taught from the three-point stance that I can see a lot of position coaches becoming worried that they'd essentially be starting over.