I like the Fredrix real canvas paper pads. They are very popular at work.
I have also used the Strathmore 300 canvas paper. I only worked on small post card size scraps but I liked it.
You may also want to look into the new Arches Oil Paper. Its a 100% cotton paper and you do not need to prime/gesso it. I have seen it sold in 9x12, 11x14 pads. I have also seen it sold per the sheet which is 22" by 30" and on a 51" roll by 10yrds