I get most of my pipes from a guy that buys beafy glass tubing from a glass blower, and blows his own(and just about everyone elses) pipes. They're thick, they're cheap, they're good looking. We usually get a nice double bubble (bubbles about the size of nickles, maybe a little bigger), around 9-13cm (4-6 inches) long. Inside diameter of the stem, about that of a pencil. Carb about the size of the inside diameter of the O key on your keyboard.
If we need a pipe and can't find him. We'll improvise. Usually we 'find' refridgerater lightbulbs in our pockets after a trip through the grocery store. They're like a thinner shorter test tube, with threads on one end. Five seconds with a propane torch, and they have a bubble and a carb. Not the best, but they work in a pinch.