Currently, Lodge and Camp Chef make production run Camp Dutch Ovens from 5" diameter (1/2 quart) up to 16" diameter (12 quart).

Maca Foundry in Utah casts heavy duty dutch ovens that go up to 22" diameter (45 quart). They are heavy enough that it usually takes two people to carry them, empty. However, they will do a fine job of cooking a 72 lb turkey, or a deer hindquarter, or half an acre of oats. I've been itching to get me a set of those Macas, except when I think about having to lug them around.

There are also some companies out there making Potjies (African cooking pots), some of which you could bathe in. I am guessing those aren't intended as man-portable cooking devices.

If the scale of my cooking ever gets that massive, I think I'd opt instead for a spit and do a pig roast, or else dig a pit and do it luau style, with all the fixins'.