So at CYW I bought a set of NOS mud flaps from Jack at Bugstuff. They weren't cheap, but they are definitely hard to find especially in good shape. These are German as far as I can tell, and the VW logo is riveted on instead of glued. They also came with brackets (for a beetle).
I thought about putting them on my bus, but I'd have to get some brackets made. Or I might just sell them instead if someone wants them.