Here are three blank sketchbooks in the Japanese-binding style. They are full of good quality drawing paper and some sketch paper. They all measure about 6 1/2″ x 8″.
Each one has a collage on its cover made with Thai handmade paper. I sometimes crumpled up the pieces to create contrasting textures to the smooth pieces. I found that the paper has slightly differently color-saturated sides, so that provided another contrast.
These cost $20 plus shipping.