I have the SRX version which is similar to the SR7 except that it offers the added protection of a laser diffuser. I've spoken with my local stereo shop about the installation options.

Mute/power button in the ashtray compartment
Display unit in the storage bin shown in the post above
Warning LED in the overhead reading light

I think that would be an ideal location. I did consider putting the mute button to the left of the PCM but that didn't look very good to me.