I recently commissioned a custom sized cover from Morgan Le Fae's Trinkets. I ordered a wider than standard A6 cover painted like a bright opal - as opal is my birthstone. Pictured is the result. The leather, while firm, isn't too firm, smells great, and the painting on it seems to be more of a dye as it really doesn't have any texture - which is nice.
Monique put 6 strands in it as I requested, so that I could really stuff it with all the inserts I need in there. I originally converted to the A6 size because I am using the Hobonichi Techo for my planner and it is an A6 size. I used to carry an A5 size which was just too bulky and heavy.
If you are contemplating a custom cover, I would consider a Morgan Le Fae's Trinkets custom order. Her Etsy shop is here and her website is here. Monique is very responsive to messages and will do her best to work with what you have in mind.
I carry my TN with me every where and use it for all my note taking, lists, daily planning, memories, thoughts, inspiration for my blog and life coaching work. I want what holds all of that together to be a thing of beauty and meaningful to me as it is protecting important parts of who I am. This cover does that for me. Thanks Monique!