Are there and actual pictures of efuses? It's probably a stupid thought, but... here I go.
I've been doing some bga soldering recently, and I thought, what if there was a a board you could put between the motherboard and cpu that would take the efuse pins (actually balls of solder

) and redirect them to your own set of efuses.
I know there are problems with this, such as efuses not being available to the public (or at least as far as I can tell). And you would likely get the rrod pretty fast from a setup like that.
Does each efuse have its own pin on the cpu, or do they get multiplexed? If not, with the above idea, you could just leave the cpu key and dvd drive efuses untouched.
edit: Is an efuse just a resistor that changes resistance When it gets "Blown"?
efuse info:
http://paris.utdallas.edu/ssiri08/Tonti_SSIRI_eFuse_V2.pdfedit: I found a pinout of the cpu, and the efuses aren't that open, so I guess this is going nowhere.