Just for the fun of it, I went to the International Sign Show in Orland. (I love my GF, but I really would like a Trotec, Epilog or Universal) Saw a lot of interesting stuff, but one booth stood out for GF users: The Wood Gallery ( www.thewoodgallery.com)
Run by a great guy who was at their show booth, their main business is custom wood cases, mainly for knives. But, they also sell colored plywood sheets. Two different lines, standard colors (purple, green, pink, red, orange, yellow, blue, bourdeaux, weathered black and black) and grain-it colors which seem to have more of a “prismatic” finish (burnt orange, blue jean, brown, purple, green, yellow). I have to say the the bourdeaux is pretty impressive, as is the grain-it blue jean.
It comes in 1/8" or 1/4". Perhaps not Proofgrade, but It is baltic birch, with whatever standards that apply there. Their process is described as “a special process that allows the color to penetrate the wood which enhances the grain of the wood. The wood and color are then protected with a sealer and sanded to an extremely smooth feel. Then it is sprayed with an acrylic lacquer to provide a very smooth, durable, and beautiful finish.” I’m putting the quote in because to me, it sure seemed very similar to Proofgrade finish.
The sheets are offered with optional masking on each side, or with one side with adhesive. Yes, I know I could stain, sand and finish baltic birch myself, but this stuff looks really good and at good prices. He indicated that the 12x24 sheets could be cut to 12x20.