Source for flat mirror glass replacement?

Can't find a good source for 16" x 7" west coast mirror glass replacement. My old Grote is losing too much silvering. It's 1995 original. I can use adhesive to glue the heating element to the back of the new glass.

A whole new mirror is less than $30 but I'm the type who'd rather repair something than throw it away.

My local auto glass supplier doesn't do mirrors.

 

I swear I bought one for this truck before but I can't remember when or where I got it.

 

NAPA guy referred me to local place. I don't know why they needed my old mirror for a pattern. I's exactly 16 x 7. I left the heating element on the back of it. They cut the new glass alright but in an attempt to be helpful they peeled the aluminum tape holding the element on and put it on the new one with new aluminum tape. Only problem is the 'tards put the element too close to the edges. [Sigh] just more work for me to peel up that tape and hope the silvering doesn't come with it.

I was nice and thanked them and now I can vent here.