If you're the impatient type, skip to 2:50 in the video to see the thing in action.
Now, compare his creation with the Shiskebab in the game (image via Gameranx):
Not an exact replica, but it works similarly and mostly looks the same. I wonder if GreekGadgetGuru wrote up some schematics? I have a super mutant problem at current, you see.
V2.0Flame Machete FallOut Shishkebab MUST SEE!!! [GreekGadgetGuru]