I bought a sheet from eBay, the new yanke glass. Took a month to deliver, fresnel was scratched and it didn't fit (was half a mm too wide) so a month without use of my Cambo 4x5 and still no resolution. If anyone has a ground glass or has seen a ground glass for my camera, let me know! In the mean time, I wait for the guy to get in touch.
Also, unrelated but what would be the best way of shaving off half a mm of a sheet of glass?
I make all my replacement ground-glasses. It takes about 20 minutes of mild labour.
First get two pieces of window glass or clear picture frame glass cut to the exact size by the local glass shop. Ask them to ease the edges to avoids cuts when handling.
Then put one piece on a pad of wet newspaper so it doesn't slide around and grind the other against it with wet 1000 or 1200 grit between. When the grit stops cutting wash it off and start again with a bit of fresh stuff. Swap top and bottom glasses from time to time. If some patches seem slow to grind selective finger pressure bends (!) the glass enough for the grit to bite. When the grind is even wash and dry the glasses; one to use plus one spare.
I got a free sample of about 10g of 1000 grit from Naxos Australia about 20 years ago. That's enough for at least a dozen 8x10 glasses.
Your local glass man should be able to grind a 1/2mm of the edge. As for grinding your own, its quite easy, just get some silicone Carbide grit in 600 from your local lapidary store, and use a 100mm square glass tile as a grinding plate. Bit of water bit of grit and grind away. Should take all of 30min.