I'd seen one of these in a knitting shop and I drew myself a picture, but when I went to design mine I didn't look at the drawing... now that I look at it, mine is probably at least twice the size of the other one, but it seems to accomodate my whole collection, (including crochet hooks!) with some room to grow. I might need to make myself a small version for current projects though.
I just finished it up last night... didn't even take too long once I put my mind to it! And I think the next one will be much faster now that I know what I'm doing.
Here it is loaded.... (for scale, the longest needles are 17".)
Here it is with the flap closed so the needles don't fall out the top....
Here it is all wrapped up.