Personally, I wouldn't ever want to be without sweet gypsy peppers. They have a wonderful flavor, nice colors (yellow, orange, red), are pretty when cooked, are easy to dehydrate or freeze.
They are also ready to pick sooner than california wonder type of bell pepper and a nice size for stuffing.
I really don't know. I don't grow vegetables to sell. I'd think you would want a sweet pepper for what I take to be a Farmer's Market. I think they would sell better than the hot peppers. Many people think that the long skinny peppers are all hot peppers. That is not the case, but I would go with the blocky bell pepper variety anyway instead of trying to educate the masses.
All gardening is local. Varieties that grow well in my climate may not do as well in yours. I suggest you talk to your county extension service, in the phone book under county government, and talk to them. Most states have information about what varieties grow best in that state.
From my phamplet from the Arkansas Extension Service, the cultivars that look like they might fit you criteria are Keystone Resistant Giant, Yolo Wonder L, and Bell Boy. I don't know how those would do in your climate and I have not grown any of them myself.
I tried to supply a farm stand with peppers. He couldn't sell gypsy's or any sweet banana pepper. People thought they were hot peppers. He didn't think it was worth the time to try and explain it to people.
Any bell will probably be good. The prettier the better. Anything that looks different, I'd stay away from (brown's, purple's etc).
California Wonders is what I always grow. Nice size fruits and an abundance of them on each plant. I also like the Ivory colored ones. They are a bit smaller, but sweeter than a green bell, plus they eventually turn orange.