So, I was putting some empty 3 gallon kegs in to make sure they would fit with the paintball bottle holder, when I glanced at a five gallon keg sitting there, and a thought occurred to me:
If I make a removable 8 inch foam-lined plywood collar, I can use the same setup for 3 or 5 gallon kegs.
What?!? Preposterous! No group of people can possibly consume 10 gallons of beer at a party! Fill it and send it North and I will prepare an in-depth case study.