We are also using 3 x 12 frosted glass. I think we're just going with stainless switchplates but I am hoping to find some that are crisp and contemporary. The stock ones have a beveled edge so I was thinking something with a more square edge would be a little cooler. I'll be interested to hear what ideas others can offer.

Lutron had plastic switchplates that looked like seaglass and other opaque glass colors in 2003 when I did my glass backsplash.

They still have Seaglass, but it is hard to see what the other satin colors in the Claro line that are not stone colors will look like.

Here is a link that might be useful: Lutron - drop down

I found this company simply by googling "glass wall plates." They have frosted glass ones, and clear glass ones that you can paint inside. Perhaps you can get a paint store to duplicate the color of your glass tile and then paint it inside these switchplates? They could work.

Here is a link that might be useful: They will also custom make jewel-toned glass wall plates.

Wow, thanks nancy! I can certainly paint the backs to match because the tile I chose matches the wall paint!
Now to find someone who can install it well.

I haven't painted and installed them yet, so you don't see them in my recent reveal, but I purchased these:

Here is a link that might be useful: Taymac outlet cover