Update!
I decided that mounting the control panel in place of the ashtray went against the whole purpose of running my audio through the factory radio--to keep the stock look. So I ran the cable up the A-pillar (thanks to Rockford Fosgate for providing plenty of it), and over to the the spot between the visors. I will admit that it was easier for me to do this because it's a Suburban with the headliner removed. Yes I did have to drill one hole, but I also weld... Now I can get one of those cup-holder ashtray replacements
Here's the before and after: