Where can I find D4 dice that are truncated tetrahedrons?
Pick up a bag of Chessex Blank d4s. (It's product number CHX29301, ask your Favorite Local Game Store). Grab a Dremel or Power Sander and take off the points. Then sharpie (or carve) the numbers in by hand. That's going to be your cheap route, unless someone decides to kickstart a project like this. Certainly cheaper than buying 3d printed versions.