I really think the Rossi Circuit Judge is the way to go. Very light, smaller framed, simple, quick, and reliable. Hornady and Winchester both sell 3 inch 000. Or you could try Winchester's defense rounds. Personally, I'd go with the 000. 5 .36 caliber pellots will put a hurting on someone. It holds 5 shots and double action, in just a few seconds 25 pellots could be fired. And on the off chance it needs reloaded, reloading is quick. If you modify the stock, companies make speed loaders for these too. I have one of these guns and I have no complaints.
Another option, Saiga .410, but I have no experience with one. But I have a Draco pistol, I wouldn't hesitate to buy an AK based gun, if I had the money.