If I remember correctly the Bolkow Monsun had folding wings as an option.
Yes, but you need to remove (unscrew) a fairing on each wing first and undo further bolts in the wing structure as well. I sincerely doubt that they have been folded often, except for MBB press photos.
Doesn't the Remos GX (EASA PtF) have folding wings? It's predecessor, the G3/600, did.