A brief list of movies which feature McGuffins in their titles where said McGuffins are replaced with “McGuffin”:
Lord of the McGuffins
Raiders of the Lost McGuffin
The Maltese McGuffin
Harry Potter and the Sorcerer’s McGuffin
Monty Python’s Quest for the Holy McGuffin
Too Wong Foo Thanks for the McGuffin, McGuffin
McGuffin McGuffin McGuffin McGuffin (Eat Drink Man Woman)