Ryan, I stumbled on your web-site and I found your page on VW powered aircraft very interesting. One or two details on the European scene, I thought I could clarify (I live in Ireland):-
Jodels: While the D-9 is still a fairly popular homebuilt, the other Jodel models are rare indeed as homebuilts. The reason there are so many little Jodels around is that they were manufactured by several French companies for years. SAN, Mudry (who now build the CAP aerobatic types) and of course Robin. Robin still produce a Jodel derived wooden 4 seater tourer. These days it's a tricycle of course.
Druine: Don't know much about the Turbi, except that I don't think it was ever a homebuilt. The Condor, a 2 seater with O-200 power, certainly was originally a production aircraft. It and the Turbulent were both manufactured in small numbers by a company called Rollasons at Shoreham in Southern England back in the late '50s. One or two Condors have been amateur built over the years, but I don't think plans are available now.
Luton Minor: A nit-pick this. The Luton Minor is a parasol design, very like the Baby Ace, but all wood.
Upside down VWs: There was a guy in the UK a few (~10) years ago who was making fully inverted VW conversions. I know it worked, because he won several reasonably advanced aerobatic competitions in a Tipsy Nipper. I have seen Nippers equipped with this engine doing sustained inverted flight. I think he called his business Acro Engine Conversions or something like that. I'm not sure if he's still in business.
Well, that's all, thanks for the excellent web-site,