Yes, there is a Graphene bitcoin fork called BTCX. Snap shot is Aug 1 and you get one BTCX for each BTC in your wallet. You create a Bitshares wallet, import your wallet key and get BTCX. Super easy to trade on the DEX. The best thing is BTCX doesn't use those ridiculous Bitcoin addresses anymore, you can send Bitcoin just like Steem or Bitshares to an account name