Since Rising board became unavail I have been forced to do some checking around and it paid off. I have discovered a Wholesale Framing shop tucked away in an industrial mall. This is a very low overhead, down to Earth, friendly kind of place. It is called "Quality Custom Framing" located at 2485 Dunwin Drive, Unit 8, in Mississauga, phone (905)569-2105, email@example.com.
She is selling Crescent 4-ply, cotton-rag, archival board in a variety of colors and finish at $12.00 per board, for a full 32"x 40" board. The catch is that this price only applies to full cases of 25 boards at a time (that's $300.00 per case) This is to reduce her cost and her involvment. It is just off the truck and back out the door for her. Also to keep overheads down, she only accepts cash or check, and if anyone is interested, you would have to call ahead to order and it would take a couple of days for her to get what you want. I recommend going to visit so you can look at samples.