The two brothers who built the Robocoin — Mark and John Russell, of Las Vegas — are still trying to figure out what to do with their contraption. But one thing’s certain: They don’t want to operate it on their own. Mark Russell isn’t even sure if that’s legal.

It’s the kind of problem that’s emblematic of the ever-growing world of Bitcoins. Entrepreneurs sense big opportunity. Regulators aren’t sure what to make of it. And all that makes the future of Bitcoin ATMs as cloudy as it is interesting.

Russell is an over-the-counter Bitcoin trader. He’s the kind of guy you can call up whenever you’re in Las Vegas and flush with Bitcoins. For a percentage of the transaction, he’ll meet you and swap Bitcoins for cash, or vice versa.