They are made by Provocraft and you can find them at Michaels etc in different sizes to suit your project. You can also find these and other alterable tins online by doing a search for lunch tin.The Cuttlebug embossing folders also fit nicely into this size tin.

You can cover this size with one 12" x 12" sheet of scrapbook paper. For Amanda's box I cut the 12" x 12" sheet into 4 strips 2" wide which left a strip 4" wide. I then cut the 2" strips to 11-1/2". There will be a seam on the sides of the box and a 1/4" gap in the middle of the box that can be covered with ribbon. Glued the first 2 strips on the back and the second 2 on the front overlapping on the sides. Cut the 4" strip to 4" x 7" for the top.
For the other box I cut three 4" strips and left a gap at the top and bottom which I covered with ribbon.
To make a template for the cut outs for the lock and the handle cut a piece of aluminum foil to size, cut a slit and form the foil around where you want to cut. trim the foil and check again for fit before you cut the paper. It is really trial and error as not all the tins are exactly the same.