OK, got you now./forums/images/graemlins/waytogo.gif
I have a factory overhead center console too, just not installed. The older Burbs could get an overhead console, not as nice as the newer ones but it was the same as the old Astro overhead console.
With the brackets my shelf kit came with there was enough room for stuff to fit in there no prob and I could still get my hand between the two to pull stuff out, I just couldn't use the center piece that came with my shelf.
The factory visors do screw back into the shelf but I had to bend the crap out of the mounting arms in order to get them to sit flush again after being reinstalled. They sit up there nice and tight now, but if I have to drop them I loose way to much windsheild to safely drive.
As far as shelves for newer Burbs, I have seen some designed to work around the console. I think they may be two pieces that mount on either side of the center console and give you two seperate shelves then.