Well, there is definately room there to set it into the dash deeper, would just be a matter of some different custom fab work. The only problem (for me at least as I have my seat most of the way back) would be how far I would have to reach to touch the screen. (The BMW iDrive isn't touch screen AFAIK) I do not want a hood sticking out of the dash either to shield it.
I still doubt that setting it back even a couple of inches will help much because almost the entire screen reflects the sunroof.
I think the best solution would be the transreflective screen... too pricey tho, I just close my sunroof cover