Roger, I'm sure one of the swivel makers can make up one that size, and with modern steel, could be made to easily withstand the recoil.
But it's gonna be Heavy!
As example, I have a late period Berks swivel with 1" straight octagon barrels, 31" long and about 50 Cal. On my bathroom scale the thing weighs in at about 17 or 18 pounds! It shows signs of being shot a lot, so someone enjoyed it.
Like some of the guys have said, you might want to consider mounting yours on wheels!
John