Pretty simple logistics actually. Set up a penalty bond using Ethereum and a smart contract. Each lodge 100% or 50% or 25% of the total BTC value in ETH in the smart contract, failure of either side to honor the original deal, the ETH moves to the winning recipient. You can have a trusted multi sig fire it or an oracle. This way no one gets there grubby hands on multi millions worth of BTC regardless of how much trust they display today. Bonus is by the time y'all get your shit together ETH will be worth double it is today or even $100. So act quick work out the details secure your ETH at today's rate, lock it up and let the games begin.