Just search online. I just search out.
They list listed many super dark sunglasses for men.
And their prices are very affordable. If you think they still not dark enough, you can also buy some tinted dark sunglasses that you can determine how dark your sunglasses would be.
The following sites are my favorites. I LOVE their shades. It's cool. And these three sites are quite popular. If you have not tried any of them, you can take a shot. If you want to know more about their sunglasses, you can check them and google their customs feedback.