there was a diaper by pathmark called the Super Toddler Diaper that was like that. I used to get them but they discontinued them sadly. It was definiteley the largest baby diaper out there, but nobody seems to remember them. I wonder if i imagined it...
The ones I have are called "Mama's Best," but they could be the same diaper sold under two different names. These are definitely the largest baby diapers I've ever seen.