I think the largest bowl is the Hyperbole or the chimney stack. I have the hyperbole and a bowl of Briar Fox lasts about an hour with measured puffing.
There may be some pipe makers out there that would be willing to make a custom bowl.
They're definitely 2 of the core pillars. I would include wrestling and kick boxing/muay thai.
I'm a huge mma fan, so I figured I'd actually see what's up. Been doing bjj for 5 years now, it's a great full body workout.