I wish I had pictures from when I was actually constructing the hat, as it is made up of 2 main side panels, four smaller side panels, and a handle--originally I was planning for it to open and close. I used large sheets of cardboard for the sides. The handle is corrugated cardboard reinforced with an unraveled toilet paper tube (for shape). The stickers (for which I used both masking tape and paint as adhesive--she didn't say we couldn't use the paint like "glue") I free-hand painted on very thin cardboard (that I found in a recycling bin).
I used the masking tape to hold it all together (the inside looks nuts) and I also used it as a design element, as the trim, which I painted red. I added a piece of clothing sticking out the side (even though I never overpack-ha!); for this I pulled apart a piece of corrugated cardboard and used the thin, papery-like side as "fabric". The luggage tag is thin cardboard and so is the "string" that holds it to the handle. The whole thing is about 4' 2" across, and 9.5" wide (and, keep in mind that I am only 5' 2" tall!). It is hollow inside, but is still a bit crazy to wear/balance--which I have to do for class.
This is it:
In progress: I used books and things to weigh some parts down while they dried. (You can see the "hinge" on the bottom in the above photo on the left).
These are some more pictures as I was working on it. Here you can see the locks and latches on top.
The result: in the middle picture you can see the "fabric" sticking out--I need to fluff it up a bit. The bottom picture is of the back. It's goofy, but it works, and I actually learned alot while making it. If I had more time, or had to make another one it would be way different but very much the same.