Arbitrage opportunities

I've been looking into the price difference between some of the different exchanges. Coinbase seems to have notably higher prices than BTC e and camp bx. I've seen on the camp bx site that they will start accepting ACH payment next month so this is very interesting to me because it would make funding an account much faster and more simple. however once this is implemented will it drive price between exchanges closer together as it will allow more people to enter the market. of course i hope it doesn't and i can profit of the price difference for a while. also does anyone know the account limit size at camp bx for a verified account. it would be most profitable to move larger amounts given the market provides enough liquidity. which leads to another question. is it reasonable to expect to buy 50 btc a day at the price the exchange is displaying. How big can orders be so that they are filled and don't stray to far from the initially set price?