I remember a 3 barrel revolver back in the '70's, or early '80's. It was a top break, with a .410 in the center, and alternating chambers for .22 and .357. The cylinder rotated around the .410 chamber. A selector on the side moved the firing pin, allowing the shooter to choose the caliber for the task at hand.
A quick google search didn't turn it up, but maybe someone here has seen it, and can say what it was.