Just try it, it's not that easy.
If buy 100btc at bitstamp now for $13289 I could sell them at Mtgox for $13600, now i gotta move that money over to Bitstamp. Probably looking at 4-5 days depending. So your $13k can make you $300 every week and you hope that receiving and sending all this fiat doesn't draw unwanted attention.
What about using Bitinstant to transfer from Bitstamp to Gox?