There's no need to be condescending. It's not a silly question. Not everyone knows the laws of thermodynamics or the heat properties of various computer components.
actually psu is a big problem along with the heat.
85 watts is the max for the mac mini. the iMac psu has more power available. currently no one makes a power supply that fits in a mini that could power the 3.4 quad. and a 6970 gpu.
the 3.4ghz quad core cpu in an iMac is 95 watts
the source below claims the gpu pulls 75 to 100 watts.
http://www.notebookcheck.net/AMD-Radeon-HD-6970M.43077.0.html
so go low and you are at 170 watts for 2 parts an 85 watts psU will not do it.
with a brick as psu 110 to 130 watts would be max
psu
this power supply is one of the biggest on the market 130 watts.
http://www.buy.com/pr/product.aspx?sku=220399066&sellerid=27095498
so this lets you have a 45 watt cpu and a 50 watt gpu in a mini of course you get a brick not a power cord.
now If you make a 130 watt brick as a BTO option and put in a better cpu/gpu
you would need a second fan and maybe just one hdd. you could get the
i7-2860qm it is 45 watts
http://ark.intel.com/products/53476/Intel-Core-i7-2860QM-Processor-(8M-Cache-2_50-GHz)
the 6870m it is 50 watts
http://www.notebookcheck.net/AMD-Radeon-HD-6870M.43733.0.html
this is 95 watts with 35 watts for other parts.
Apple could make this work if they want.
this would be the best they could do in the mac mini if they add the 130 watt brick.
it would be quite a machine. it could handle 16gb ram ddr3 1600 but they won't make it. too bad. it could run a great ht/game room.