Well, so then I must have been on a different forum where a couple of guys offered exactly this: leasing hash rates, a.k.a. mining contracts. Actually it's because it makes a lot sense not just for the seller but for the buyer as well. Personally I started setting up such a service as well
and I don't see a problem in offering such thing. It's (almost) just a matter of the right price, no? And trust of course.
Oh, sure, people are trying to lease hash rates. What I meant was, if you look at the amount of money being spent on leasing computer equipment versus leasing computer *output* (of any sort), there's no real comparison.
Here's the problem which nobody has successfully addressed: Why would you lease me your hashing at a monthly rate that is less than you would receive yourself from mining? Conversely, why would I lease your hashing at a monthly rate that is more than I would receive from the value of the coins?
See, either way somebody loses. Thus, there can be no trust, because there is no mutual benefit. Business 101.