Well, you could shop the world of motorcycle helmet accessories. Without posting so many links right off the internet, you can search for Helmet accessories, visors, and mirrored visor tear-offs. On the less expensive side, HJC offers a lot of mirrored visors in pink, blue, silver, rainbow, and gold as an example. But these are hard plastic visors that aren't as flexible as, say, welding shield plastic. They flex, but only a little and are in the $30 range. And if you saw into them, you have to give the size of your field-of-view a wide berth, because the mirroring can chip. The best option might be what are called "tear-offs." You knee-draggers out there know what I'm talking about. Tear offs are thin, very flexible, and are made to quickly tear off your helmet via a small tab when you've accumulated too many bugs and rubber going 140mph. They sometimes come in packs and might be around $20/pack. Yet, I'm not sure as to how many color options might be out there...I've only stumbled across "mirrored" thus far. You might loose some durability with a tear-off, but if you don't plan on touching the visor much, they might give you the look you're going for. Good luck.
or, i was thinking bout some tint for my car headlights, a light blue, and anyway, i was looking at some stuff, and here is the idea. buy a grinder face shield, cut the "T" out, and buy some mirror window car tint. its illegal on cars, but, would be perfect for the chrome visor. you just basically peal and stick....this will also depend on what type you get.