Kilt hose for giants

[AtlantaRandy]

I may have the yearly award for odd questions wrapped up with this one. We're attempting to assemble presentable formal wear and running into one issue.
My 18 year old son, a college football offensive lineman, is 6'7" 315Lbs. and is a dedicated power lifter and strongman competitor.
He wears U.S. size 16 EEE shoes. We have to have his cowboy boots custom made to fit his calf muscles.
Needless to say, the kilt hose I've found so far have not been available in the sizes needed to make him presentable in a formal kilt situation. We are in desperate need of larger size hose.
Can anyone recommend a retailer that might carry such an item? I'd prefer to NOT break the bank but any option will be considered.