Up to twenty people but great for 2, huh?
Welllllllll my answer to that question might not be orthodox.
Currently, I travel with a Weber Go Any Where which works for up to 5 people (depends on the menu) and then just add on as needed.
Add-ons could be utilizing a camp fire/a Coleman white gas stove/ patio sized Weber as well.
It took some time but I decided that cooking for my core group (up to 4) was fine for storage purposes. No longer have a problem telling/asking excess guests to bring a heating appliance and taking it home too.
I'm a charcoal cooker.
HTH.