With the cost of mining being dominated more and more by the electricity bill, I started thinking in embedding miners in these appliances called "electric heaters" (see pictures
http://goo.gl/VC4YNx ), and then sell them at a discount price (bitcoins mined to my address) or full price but with the ability of sending the bitcoins mined to any address. These heaters are not the typical HVAC units that use heat pumps but simple "electricity burners" that are very inefficient. The people buying these would waste the energy anyways.
The miner should be some tiny linux computer such as a raspberry PI with a GPRS modem and an array of bitcoin ASICs that will be insulated and submerged in the oil that these heaters use.
Some numbers:
A heater typically burns 2KW
Assuming a heater stays on for 8 hours a day during 3 months = 720 hours
Asic efficiency 1.73 GH/s per KW (Black Arrow Prospero X-3)
Total GH/s ~ 1.73GH/s x 2KW ~ 3.5 GH/s
Earns x hour ~ 1.48 USD / 24 ~ 0.06 USD (today)
Earns x year ~ 0.06 * 720 = 44 USD
GSM bill x year ~ 60 USD
So if we are not taking into account the capital expenditure we are almost even. Give one year more and prices of ASICs and all electronics will fall, bitcoin will probably raise and we are on the path to profit.