I think you guys meant the R12, great suggestion.... totally forgot that gun existed. Unfortunately it seems to be unobtanium.
Versamax Tactical is 22", and marked for 3" shells.
Pretty sure Tactical Ordnance can shorten it if you wanted to go that direction.
Officially the gun is 3" but Remington confirmed that it is a 3.5" gun (they issued an official statement confirming it is 3.5") and I'm 99.9% sure I have seen shotguns built by Tactical Ordnance with the 3.5" marking added.