I think I read that the Maxpedition Proteus waistbelt fits up to a 45" waist, FWIW.

I've given up on being able to get a belt to fit me (at least a 50", but I like extra length to allow for different clothing options). I just buy several feet of appropriate 2" webbing, & re-do one or both sides of the belt myself. I've hand stitched several (with no problems), & had one commercially box/X stitched on an I-frame backpack.

David