I should have probably sketched out general ideas of what I wanted, but I dove right into making a prototype. I had a general idea of what I wanted to do, and it took about 20 minutes to make. There are some problems with it, but it's serviceable and will act as a base for any future cases.
First, I took some left-over fabric that I used to create my Rosie the Riveter bandana, and cut out a 17.25 x 9.25" rectangle; the seam allowance will be about 0.25". The final piece will be about 8.5x 9.0.
Then, I cut out another rectangle -- 4.25 x 9.25" to act as the pocket, and sewed it onto three edges like the below photo)
I turned the whole thing right-side out and sewed the last opening shut. Afterwards, I created channels to fit a variety of knitting needles, pens, and pencils.
The flap folds over and the ribbon wraps around it to form a fairly compact case.
I thin I'll re-make this again with different fabric and make it a bit better with additional closures, but for now, it's a workable prototype.