A small portable Obutsudan can be cut and folded from one sheet of paper. Card stock or heavier works even better. This is intended for traveling or for visiting someone in the hospital, and may even be acceptable in prisons and such places where they get nervous about anything solid.The plans can be downloaded and printed on 8-1/2 X 11 paper. The paper can be taped to black, red, or wood-grained card stock or poster board as a cutting guide. It can be decorated however you want. Pictures of the Buddha or copies of the Nembutsu can be downloaded elsewhere, like our "clipart" page. After they are printed on white paper, they can be pasted into the Shrine.
I chose 8-1/2 X 11 for ease of printing (actually it's a bit smaller, since most printers won't print all the way to the edge of the paper), but if you have the technology available, like for instance, you live near a Kinko's or other good copy shop, you can vary the size. The size I offer makes a shrine that is just over 6 inches tall. Here is a fuzzy polaroid of the test one I ran off, not colored in.
Here are the plans. The first set is just the outline, no pictures, because you can probably build two or three of these while you're waiting for the full-color version to load. Not to mention waiting for it to print! Cut on the black lines (X-acto knives seem to work well), fold forward on the red lines and fold backward on the green lines. It folds more neatly if you score the lines with a blunt knife or a crochet needle first. It has tabs that fit into slots etc. to hold it up better.
Here are plans with color and a picture of Amida Buddha. This style is specifically Jodo Shinshu, and a little more ornate, but I guess you can download it and modify it if you follow some other tradition. First the inside then the outside. Make sure both are centered on the paper when you print them.