There are also some (not many) Spanish 2" 12's floating around. Arrieta has made some. They're heavier than the Brit 2" guns, and carry the modern CIP standard proof for a 12 bore. Friend of mine had one. They're unique, but I think I'd probably go with a 16. On the other hand, I have a Webley & Scott 700 that doesn't weigh 6 1/4# and is chambered 2 3/4" which makes it quite versatile--although I'll stick with 1 1/8 oz loads at the most, and more likely 1 or 1 1/16 oz.

There are really light 20's and 28's out there, with ammo readily available. Seems to me that's the route to go if you want a light gun to shoot light loads.