Vector copy (.SVG) of my micropul box. My tiles are 3cm square and mounted on cereal box carboard, this box fits them with plenty of room to spare. This box should fit up to about 3.5 cm square. You might be able to fit 1/8" thick tiles in this box, but it'd probably be a squeeze.

Editing the svg in Inkscape (free vector art software) should be simple enough if you wish to resize the box to accommodate other size tiles.

Assembly of the box should be reasonably straightforward.