I have seen a few Extra Large 5.5 X 9.97 Moleskine soft-cover notebooks, and also the extra-large cahiers. I have never been able to find the ruled variety: I understand the soft-covers haven't arrived yet, and someone always gets to the cahiers before I do. Rather than experiment with a blank soft-cover at $20, I bought a pack of the Cahiers.
I've liked the idea of Rod Graves' <a href="http://rodgraves.com/moleskine/">template</a> and tried to make my own the same way. My math skills hadn't atrophied to the point where I couldn't convert the 1/9 and 2/9 margins to what I hope were decent measurements. However, I had to trim the inner edge of each template by about 1/4 inch or they wouldn't slip down enough beneath each page. I suspect this will change as I work my way towards the center pages and back out again.
I think this leaves me with about the writing room of a ruled large Moleskine, but with plenty of room on the margins for glosses or even sketches. Also, if I wanted to leave a page blank for sketching or to insert an illustration, I have that option.
Here's a few pictures of the result. In the first few pages, the notebook chronicles its own design.
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