Roof racks for Avant - any compatible OEM versions?

[eljay]

I am a complete newb when it comes to roof racks and I don't particularly need any at this point, but I know it's only a matter of time. Anyways, every now and then I see OEM roof racks for other Audi models pop-up and I'm wondering if any of them are compatible with a B6 Avant with rails.
For example, can I use Audi Q5 roof racks?

Thanks!

p.s. I know Yakima Whispbars and Thule are the recommended choices, but I'm not at a point where I need them, so not looking to spend $$$ on those.

[Toronto5.5]

I think b6 and b7 racks are the same for the avant. But that's about it.