Nowhere do I go without my sunglasses, and likewise, my rides always sport nice shades as well. It's the least I can do for my companion, after all there is privacy & fabric to protect!
Tint My Ride (VT) did the work for about $200 (spendy, in my opinion, but worth every penny).
COST (FOUR WINDOWS): USD$190
ODOMETER (MILES): 84220