I'll give you a pipe i made tonight with a Bic style pen, smallpill bottle, socket wrench, piece of window screen, and a hot glue gun. It's really small and stealthy.
Take the small pill bottle (I used one that had the robitussin gels) and make to intersecting cuts into the side of the bottle. Then get a socket wrench and put a peice of window screen in the bottom of the socket, this will be your bowl. Take apart the Bic style pen and cut a small piece of the tube and hot glue the bowl onto the Tube. then stick hot glue on the entire pen and stick it through the intersectin stabs and if you do it right it will have an air tight seal.