I saw someone on a property makeover show recently, wanting to do what you're doing, being informed by the presenter that he had to use special toughened glass and that it would be massively expensive.
There are a couple ways to get frosted glass. One is to buy it from a glass shop but that normally is expensive.
The best way is to look for some used glass, and if it is heavy all the better, then find a good sandblasting company and take your glass to them and then put it on a sheet of plywood and have them sand blast it to the darkness you wish. I have done this for many years for glass companies and they make a lot of money.
It is a cheap wya to get frosted glass.
The sand blasting will cost a small amount only as it does not take much time or sand.
Hope this helps.