I find it weird not one card is single slot, 107W isn't all that much. Even if a slight underclocking to get to single slot.
As for comment near end of article about it not being compatible with PC due to lack of 6/8-pin connectors, that's just 30W extra, and even lowest end OEM configs have at least ine or two additional molex or SATA power connectors, so a 1$ adapter to 6-pin should solve that. May not fit OEM miniITX builds that weren't designed for it (probably due to power supply limit, not cabling), but I doubt any OEM PC in several years is out of reach for this. Yes, there are some that can't even accommodate a single extra HDD, but in my experience those are minority.
Anyway, I also guess 6400 will be there soon for both of above cases, single/slim cards and no additional power.