The actual "trick" behind this is well known and has been done for quite some time. One could actually solder in a different device id in the GTX 6xx series [0] or flash a different VBIOS on the GTX 5xx ones. The real achievement here is implementing this in software without touching the GPU.
This is not to downplay the OP, of course - this is truly great and I'm sure it was a lot of work. But the hardware part is not new.
