Actually, saying that THE NINES was helmed on SD cams isn't entirely accurate. The film has different movements (a.k.a parts) and each movement uses a different format.
Part Two was the only part of the movie that was shot in Standard Definition. The rest of the movie was shot on 3-perf 35mm and Super-16.
If you don't believe me...
http://johnaugust.com/archives/2007/the-nines-as-planned
...straight from the horses mouth.
You're probably right. That's not the same John August entry I read, however. The one I read talked about them switching from film, to HD, to SD BUT I do know that each part was shot differently so I wouldn't doubt that you're right.
It still means that SD is still good enough for Big Screen and named talent, so why isn't the HVX?