I was curious on that too. The Ebay link SR-22 posted is for the barrel only, which we all know is an easy 10-22 swap. It's interesting that the barrel only costs more than a base 10-22 typically is. The barrel I know can be sold through the mail. This gunbroker auction included the entire gun which with a simple barrel swap could be converted back to a regular 10-22, so I'm betting (no guarantee) that it would have to go through an FFL. I'm not an expert though. It is an interesting concept I have never seen anything like that. I have looked at the soda can launcher uppers that they have for AR's. They use 223 blanks and look like a blast, but I cant bring myself to shell out the $350+ that they were going for.
That golf ball launcher is interesting, I'd rather make them bounce shooting one with the 22 thought haha