Ever since I bought my VX a couple of years ago, all I read was that nothing except the OEM Yaks would fit those mounts. I decided yesterday to go check out the local roof rack store and, after trying a number of different fit kits, we found one that actually works!
The important part is: Fit Kit #4002 Audi Q7, 06
Other parts in set up: 480R Rapid Traverse Foot Pack, ARB47B AeroBlade Bars
It definitely wasn't cheap, but I finally have racks!