Blytheking makes stuff and sells them at Etsy, the last line on the product blurb caught my eye,
"I made this case to fit the large size Moleskine notebook (5×8.25", 13×21 cm).
My
original design features security strap with button closure, and
back-strap, handy for hooking your pens onto, for tucking papers under,
and for securing case to your bag or body. Front pocket measures about
4×4.5".
Made with vintage Pendleton wool fabric, and vintage button.*
*No new materials were purchased in the making of this product."
Just in time for Earth Day, yes? 
Check them out
