I have found some interesting reference material for the forcepike. From what I have found here and talking to other guards this seems not to be well known yet. A while ago I had some discussions with a few other guards from my garrison about the actual material and shape of the production used forcepikes. The most wide spread theory seemed to be that they where made from ski poles and the shaft of the pike would be straight (same diameter everywhere between top of the grip and rasp). However, a production blueprint shown in "Star Wars: The Blueprints" indicates that they are actually made from fishing rods and the shaft is a truncated cone (diameter just above the grip is almost twice the diameter just below the rasp).
The image below shows the blueprint next to a reference image from behind the magic. Most of the features shown in the blueprint are more or less easy to spot on the reference image. So the shown blueprint is actually a final (or close to final) version (which is not the case for all of the blueprints from the book).
