I have created a market-making bot that is now operating on Hive-Engine. It has approximately 0.04 BTC in SWAP.BTC and SWAP.HIVE. Currently, it is creating more liquidity just for BTC / HIVE pair. The rates do refresh every ~10 minutes. Max commission (difference between rates of the bot and rates taken from bigger exchanges) is 15%, the lowest one can be 1 %. It also has the ability to buy/sell BTC to those whose open order the bot finds profitable to take.
So now... if you would like to exchange your HIVE to BTC and withdraw (or the other way), you can do it right on the Hive-Engine market. Enjoy!