Just plug the numbers into an online mining calculator. If you had your hands on those machines right now you would be making those insane figures. I already did the math, with a $40k investment - even at a relatively high $0.10c/kWh - you would make about $500,000 a year or $42,000 per month (shorter time frames for mining are better to look at for profits).

The difficulty however is expected to shoot up in a couple of months when people start firing these things up. However I expect the price of Litecoin to rise right along with it (as history has shown) - especially with everything going on with altcoins recently - and specifically Litecoin. It all depends on how much risk you're willing to take. Me personally? I'd risk it all for the chance at making those kinds of numbers, especially with your low electricity rate. Those kinds of numbers are life changing, for me at least. When I have the money in a month hopefully there will be a batch available, I'll be grabbing 30-40 and setting up a small mining operation.