At first read through, I thought you meant a double or triple barreled gun. Hmmmm, I've had single shot break open guns but never one with replaceable barrels. I almost got hooked into a Thompson Center pistol like that once, but I'm too hooked into guns with magazines.
Although, you mentioned a youth gun. Something like that might be perfect for letting loose a kid going hunting. My folks would cut me loose with a break open .410 when I was about 12 or so. For the money, it sounds like you would get a versatile 3-caliber gun for use for just about any need.