I don't have time to code this myself, so I'm gonna make a
40k 80k 160k BTS bounty for a metaexchange->shapeshift->blocktrades arbitrage bot.
It should automatically work out if there is a profit to be made through arbitrage between each of the instant exchanges and then actually be able to make the trade (by sending funds from the relevant wallet) and record the actual results (by monitoring wallets and exchanges) along with the expected result in a mysql database.
Blocktrades.io doesn't have an official API, so the author will need to use cunning to get this to work
edit: oh, and this should be made open source as well, github