I've been thinking about making one so I have something to do at 4H meetings instead of sitting there, not really wanting to listen to the business meeting. All the talking is too distracting for reading. I've crocheted before but it's kind of bulky to take along.
So I came up with the idea to use this container I got at Michaels several years ago in the beading section that came with some tools. I had some alpha beads in it and colored wire but it wasn't really being used. It was perfect for making a small, portable card kit. It opens on both sides - one is all open and the other side is divided. I used a piece of thin foam on the divided side to keep those little bits of paper, flowers, and brads from migrating to other areas when it's being moved around and flipped over.
This side holds a few catseye inkpads, mini gel pens, a glue stick, and all sorts of embellishements: flowers, rhinestones, pre-stamped greetings, brads, flowers, and more.
This side holds 4 1/4 x 5 1/2 cards perfectly (the size from cutting a letter size sheet in half and folding). It also fits some pop-dots, glue runner, embossed card fronts, and some other large pieces.
The hard part was trying not to stuff it with too much!