I would think you could also do these in the oven - with tomato sauce/liquid in the bottom and covered w/foil so they don't try out!
We also have a HUGE crockpot, and I do sometimes put a whole chicken or big roast in there for the 5 or us. I'm sure a smaller size that would fit 2-3 peppers could be found? I would check other non-crockpot recipes for timing and temperature.
P.S In my hunt I found the following (which is basically core if you omit the raisins!)
BELL PEPPERS STUFFED WITH BARLEY
1 c. pearled barley
6 med. green or red bell peppers
1/4 c. chopped onions
1/2 c. raisins
2 tbsp. chopped fresh mint or 2 tsp. dried
3/4 tsp. ground cinnamon
2 tbsp. lemon juice
Cook barley in 6 to 8 cups boiling water for 30 minutes; it should be tender but still have some bite to it. Drain and reserve for later.
Preheat oven to 350 degrees.
Cut 1/2 inch slice off stem end of each bell pepper. Discard stem but chop up what pepper remains and reserve for later. Empty peppers of seeds and ribs.
Spray a large skillet with Pam or Baker's Joy; add onions and reserved chopped peppers. Stir fry for a couple of minutes. Add 1/2 cup water to the skillet, cover, and simmer over low heat for 10 minutes or until vegetables are tender.
Add to the skillet the cooked barley, raisins, mint, cinnamon, and lemon juice. Stir around for a minute or so and remove from heat. Season to taste with pepper.
Scoop the barley mixture into the hollowed-out pepper cases. Fit the peppers into a baking pan so that the peppers touch and help support each other. Add about an inch of water to the pan. Cover and bake for 45 minutes to 1 hour or until tender. Makes 6 stuffed peppers.
Serving size: 1/4 recipe - 193 calories, 77 grams fat, 0 cholesterol, 6 milligrams sodium.