Here is a piccie of my friends Hellcannon. Completely scratchbuilt for about £1.50 he claims. It makes a nice addition to his 2500 point Warriors of Chaos Army.
Basically some plastic tubing, milliput and chain from a piece of junk jewellery, a bottletop, a couple of chaos shields and some time and effort. Kudos. The crew are not scratchbuilt (if they are I am truly in awe!!)