Let's put that into a calculator.

$800 for 100GH = 1.21BTC

Over the course of the next year you'll return to me ~ 0.92BTC.
http://thegenesisblock.com/mining/a/d45da12d39

hmmm...so basically you are stealing 0.0029BTC per GH from gox victims, and stealing even more from your regular customers?

Why even bother with the mining?  You could offer better "contracts" without even needing any mining equipment...

SUPER DAVE CONTRACT:
Give me 1.21BTC now and over the course of 1 year I'll return to you .08BTC per month!  That's like 4% better return than cloudhashing is offering to gox victims!
*This is not a serious offer for any dimwits reading