Odd, I've never seen an "official EVGA" 8-pin to dual 8-pin adapter on any of my G2 series supplies - was that a specific thing to the 1000 watt model perhaps?
Their dual cables are NORMALLY one 6+2 and one 6 on the VGA end.
Mine are actually GQ's, not G2's, but I bought (4) 1000W units last month and they each came with (4) 8-pin to dual 8-pin (6+2) cables.
Not sure if it was specific to the 1000W model, but I know the 750W and 850W models do not come with them, because I have some of each of those.