The issue I see with this is that the VRM layout on the 970 and 980 is spread out more than you would see on a 780 or a 290. If you look at the thermal pads on stock and aftermarket solutions, you can see the area of the VRM cooling required. Looking at the parts, you can see there are no push pins to mount anything, plus the VRM modules are not such that you could use tape or epoxy to get contact, you would need a thermal pad, but there is no way to mount it.
With VRM temps running into the 90s on out of the box solutions with cooling solutions attached, I don't know it would be all to recommendable to run this particular card without any VRM cooling. Perhaps re-using a plate/shim on a card that comes with one might be an option?
I have yet to see anyone actually install the G10 onto one of these cards to test VRM temps, but I would think that it is going to be more of an issue than it was a 780 but with more difficult to cool VRM parts.
I am looking to upgrade a 290 to a 970, but only if I can overclock it using the G10/X31 configuration I already have. The 290 was easy to get VRM heatsinks on, as there is a kit you can pickup and while you don't need it at stock, to overclock it, you really really do.
Hopefully someone will upload some info soon, or I might just pull the trigger and upload my results. I really like the 970, but mostly only if I can overclock the pants off it.