This is just crap, if they have profitable mining rigs then why don't they run them for themselves and collect the coins instead of renting them out. Something smells. Nobody in their right mind would rent our mining power for less than what it makes.
There is time value to money. Money today is worth more than money tomorrow.
This is actually a great business model for expanding a business. They get ~6 months of BTC up front that they can use right away. Their risk is reduced and their ability to compete improves. For example they will be able easily afford a lot of scrypt ASIC miners now.
I see your type of attitude a lot on these boards. My guess is that you have never ran a business. When you are running a business you normally want to grow it. Since the have the space, power and skills to build the hashing power there is little risk in selling it and building much faster than they could have but just using the power themselves. This allows them to actually make more money with less risk.
You can debate the price but the concept is sound. It can also be a very good deal for the purchasers who are saving on time, skills and the costs of setting up their own equipment. It also provides more options for managing the risk of mining. It can be a win-win deal.