I did a bit of a search and found nothing on this....sorry if I missed something.

Has Canon come out with or even suggested manual control of audio(through a firmware update) of the 7D?

For reference, I worked with the 5DMKII(that I owned) that had firmware updates that gave audio more control.

Anybody heard anything re: audio control and the 7D?

Tx

There's nothing to indicate that will happen.

I used the JuicedLink DT454 mixer with the 7D. I use it, I love it and it has worked well for me. Having headphone monitoring, seeing levels is wonderful. I also used the AGC defeat. It did as advertised. I had good clean sound on channel one and noise on channel two. I would highly recommend it.