A crowd sourced cash out. I would never expect to get the full 1 billion dollars, so I'm basically going to offer the bitcoin at half price to whoever wants it, payment being in monero. I'd possibly set the price lower if demand is low, but adjust depending on how demand and monero value fluctuations go. I think people would buy the coins, especially if there's decent publicity and marketing. Frame it as free money for whoever wants it, and I would walk away happy with anything more than $100 million and my anonymity.