If you have the W8 overhead console, I wouldn't be too worried about a mirror with downward lights, I'd go after a more feature filled mirror.
Audi A4/A6 (B5 & C5 chassis) with a compass display, I like the squarish body on these.
Audi A4/A6 (B6/7 & C6 chassis) with a hidden compass, I actually (painted &) swapped one of these on to a rain mount base. I liked it, it was cool, but the rounder body isn't my favorite.
VW Passat (B6 I think) no compass, but neater/newer square design, no additional features.
Saab/GM various years, has both compass and homelink functions, more work and a blue compass display, but more features.
Almost all of these can be swapped into the ball of your rain mount, if your rain mount is the later style with the larger diameter ball.
As for painting them, it looks okay and is acceptable for normal use, but give the amount of time/money you're putting into the comfort creature mods you've been doing, I'm not sure you'd be happy long term.
It's worth mentioning that almost all of these mirrors use 1 of 2 different connectors on the PC Board and you can re-pin the other end to use the rectangular 6 pin VW/Audi you mentioned above.
I've had my hands on and taken apart MANY mirrors over the last few years, so feel free to ask any questions.
Hope you can get the function and look you want from this mod.