Bronze is still a popular choice in exterior window color on many custom homes. In fact, it is absolutely an essential with some exterior facade colors. 
The downside to the bronze window is that it is only available in aluminum or wood-clad window. These are at either end of the price spectrum and for the most part eliminate the largest segment of the window industry. There are a few manufacturers who produce a vinyl window with a painted bronze exterior. There are two reasons we don’t sell them: first, on a sunny elevation fading has been a problem. We’ve even had a few that have bowed due to the excess heat. Secondly, they are an expensive window. I think if you are that close to the cost of a clad window you should use the clad window. As far as aluminum goes the selection is basically limited to aluminum single hung or fixed windows and is not much of an option for a custom home.