I've imagined many times my dream notebook. Too much thinking but doing nothing. However I had clear each detail in my mind: Size, thickness, leather cover, verge paper, full flat when open, etc.
Some reasons to encourage you to do your own notebook:
1. It's the only way to have it as you want. It's almost impossible to find your perfect notebook in a shop. Fortunately nowadays stores shows plenty of books with a number of brands never seen before. Most of them contain paper with non acceptable quality. If you like the paper but maybe not the cover, you get it and time later you realize it's not your perfect jewel because you see only the mistakes.
2. It's made with love. No industrial process. Everything takes energy and it's not the same if it was been created by a salaryman without any care than done with your own hands with passion. See how bookbinding is done here: http://josenaranja.blogspot.com.es/2015/07/about-bookbinding.html
3. A strong link is created with your notebook. This is the key. A mystical relation which will boost the creativity and will appear in each letter and drawing. Fountain pens note these details, you know, right?
The result can only be a beauty because it's in touch with reality.