Personally my business model will not be to sell hashrate or mining contracts. I would set up a new corporation for the customer so the full tax benefits of depreciation pass through to them. The customer would be a non-voting 100% owner of that corp. My parent company would charge the mini-corp a fixed $/kWh rent rate or something + a setup fee. Whatever profit is left is paid out to them as a distribution every month or so. Still need to talk to a lawyer to make sure this is a sound idea.