I designed an organiser a while back based on my Filofax Metropol. My plan is to make this out of heavy-duty tarpaulin:
I made some changes like removing the big pocket over the whole cover (as seen above) and adding in a ‘flap’ that will cover the long side of the open end of the organiser (see below):
To figure out how this would ‘feel’, I created a small scale model out of paper (it’s 9 cm wide; I think the actual organiser will be around 15 cm wide, a little wider than my Metropol Personal):
I might be able to make a pen loop in the ‘covering flap’. It would be a good place, better than inside the rings, as the pen won’t interfere with flipping through the contents.
As said, I want to make this out of heavy-duty tarpaulin (the stuff they use on the side of lorries and for some types of (motorcycle) backpacks). See my earlier post for sewing trials on tarp sample pieces.