Why not just use a service like Genesis-Mining.
For 360 USD a year, you can purchase 2Megahash, which the eqv rig you would buy, would cost you a lot more.
Plus that also covers electricity and you don't have to worry about the noise or the heat it would generate.
Just a thought anyway.
They are doing a promotion at the moment, 2Mhash for 280 USD, only for a limited time though.
Just a thought.
www.genesis-mining.com