I have had black on black. Thought it would be unbearable here in AZ. Wound up, it didn't seem much warmer than my lighter colored interiors. Obviously, it had to be. I think the tinted glass and rear window shade helped a lot. Yes, black shows dust, especially in the crevices, but nothing a damp cloth won't handle. Easier to clean than the light gray door kick panels on my 535. Need chemicals to clean them.
On another note, today I planned on ordering a 2011 528i, Alpine White over Cinnamon. Exactly what I wanted was on my dealers manifest, so I actually am getting it out of stock when it arrives in late August.