Do you think that people don't look at these things? Also, I am pretty sure that putting a copper heatsink inside a receiver would be more expensive that just getting a bigger power supply.
I got a chance to look at the TX-SR805 this weekend, up close and personal at the showroom in Circuit City. The bugger weighs a ton because it has a big power supply. The case is not to different from the case to the TX-SR804, it is a tad taller and the face plate is different. The heatsink is aluminum believe it or not, and the feet are not filled with lead. It is a heavy weight contender and it deserves the THX Ultra II certification.

Onkyo is not a white van scam company or a fancy pants audiophile piece of equipment. It has what it needs to get the job done, it would be a horrible mistake for them to suddenly add dead weight to the receiver.