Man, that enclosure is looking good. Very nice work!
On the antenna, I was looking around at these guys:
http://www.tunetrapper.com/Hidden_Car_Antennas.html
They sound more like amateur radio heads and seem to know what they are talking about based on my past experience in amateur radio. But, I haven't tried it so I can't say if it works. Curious if you tried something like this or one of the hundreds of "amplified" antennas because I was thinking the same spot as you, behind the dome light between there and the B pillar corner. But your luck may be changing my mind. And of course, our cabs are just metal cages which doesn't help. Thanks for the update on the details!