Bitcoin mining video card chart

Considering $1000 rig, $0.2 per kWh and one year breakeven perid, at which difficulty GPU mining becomes non-profitable?

Or, what is the formula to find out "max non-profitable Mhash" for given parameters like, rig cost, power consumption, investment breakeven period, difficulty, exchange rate, etc. (please ignore redundant parameters, and include more parameters if required.)

Or, whats the current "max non-profitable Mhash"?

Or, what is the required current energy efficiency (Mhash/J = millions hashes per joule) for mining to be profitable?

(energy efficiency; 1 joule of energy is 1 watt during 1 second: 1 J = 1 W*s)

For given parameters, Max. Non-profitable Hash Rate, is breakeven point for hash rate after which mining becomes profitable.