I have just ordered this from Strawberrynotebook on Etsy, owned by Diane who is really amazing to deal with. Mine will be the standard Midori notebook cover size, but extra wide as I am an overstuffer. I chose a mini Tardis charm (you have a choice of several charms related to Doctor Who) and to have the inside dyed to be the same colour as the outside. Diane has promised to send me photos of the progress so I can share them with you.
She has also this gorgeous labour intensive wood effect leather which she will be using to create notebook covers. All the flooring effects were done by hand by Diane so it must have taken ages!
Then, I finally managed to get hold of some Midori lightweight paper notebooks. Every time I buy from the Journal shop they have oversold the notebooks or else they are out of stock. So these ones are on their way from Goulet Pens. I love Tomoe River paper so this is the next best thing until I can get Midori notebooks in the same paper.