Hey AJ, you seem to be ready for my patented "I hate this head unit" last resort removal technique.
I did post this somewhere on the forum, but can't find it now.
You need to prise off the front of the head unit, it's only clipped on. This will give you access to the metal frame behind and you'll be able to see what the problem is.
You may want to stick some gaffa tape around the aperture so that you don't scratch it.
Using a wide thin piece of metal, slide it between the aperture and the bottom of the HU's front panel, about a third of the way in. Lever it up so that it pulls the bottom of the front panel up. Do the same on the other side. You should now have the bottom of the front panel free. You may be able to lever the top off now, if not do the same to the top.
With the front panel off you'll be able to access the gaps were the metal clips have wedged themselves. Don't try and unscrew the front panel (like I did) as you can't remove it from here. Now you can see what is going on you should be able to fiddle around with the clips and the frame to get the b*stard out. I had to do this a few weeks ago on my mates A3. He'd finally given up struggling with the sh*teness of the Concert and now has an Alpine. The unit will still work, at least as well as it did before removal, just clip the panel back on once you've got it out, and don't ever, ever put it back in.