I have Behr's "Mountain Haze" in my kitchen (had it mixed by my BM dealer) and love it. It's a very soothing sage, light and airy, not heavily gray, subtle silver undertones. Very tricky to photograph (photos do not do the color justice) I have a couple below against the white cabinets so it shows better.

First one in low light and second one in high light:

RH Silver Sage is very popular. Check out the home decorating forum.

I found a silver green at Wal-mart and bought the
Dutch Boy paint. It is named Silverberry and is a little
lighter than Silver sage. I was very pleased with it.

Benjamin Moore "Gray Mirage"

Benjamin Moore's Gray Wisp is an exact match for Restoration Hardware's Silver Sage.