Not really a QRP project (the goal of course is definitely QRO) but Knack victims will find this article and the associated video interesting. We’ve covered homebrew fusion before. This fellow is the 38th successful “amateur fusor” in the world. Go Brooklyn!
Homebrew Fusion Reactor in New York City

You know who invented the Fusor, right? Farnsworth! 73 de KC7IT
For what it’s worth, one of my friends (a high school student) did this at a much lower cost http://fusion.wsyntax.com/ It’s well documented with some great videos / explanations.
This thing’s made in New York City! New York City??!!??!! Get me a rope! 73…….Steve Smith WB6TNL Far from NYC
Looking forward to the day I can fit one the size of a 9V battery inside an Altoids tin next to the QRP rig. Remember the Alexanderson Alternator?