As for techniques, there's a picture in one of the summer build-off threads of one that someone made from two nose cones with a shout piece of tube used as an "inside out coupler." It was posted as an aside, so there's no real detail. It wasn't as fat in the middle as the iconic ones, but one might be able to find (or make) shorter ratio cones. If the straight section is too long, you could cut the shoulders down until there's only a very little bit left, just the minimum for gluing. The tip is cut off of the aft cone, obviously.