Thanks for the replies all. I found some hair rollers that might work, though it looks like they might have a metal spring in them. :\ If I don't get those I'll just buy some plastic pipe and make my own holes, since all the ready-made perforated PVC pipe I found has a diameter of at least 3". I'm looking for something more like 1/2".
My Darlingtonia setup has some similarities to that Sarracenia rig in the link... The main difference is that instead of a layer of styrofoam at the bottom, mine is just all soil but drains into a separate pot where the tubing is (I did it that way because it's easier to check the water level). Here's a simplified drawing of how mine works: