As someone mentioned at the beginning about Atlex, we do carry this product. Canson doesn't have the 11.7x16.5 available, but they do have the 11x17 and larger sheets. I've attached the link to our page with all sizes available.
Thanks, but I really do -- well, I guess it's now
did -- need the A3 size, so I cut down 13x19 sheets and am throwing away a bit of paper. Oh, well...
And Yes, for future reference, I did send an email to Canson about the availability of the A3 size, but I haven't received a response from them.
Lastly, I'm already an Atlex customer, as that's where I buy most of my paper and all of my ink. 8^)