|Allegedly Marco Polo's Own|
The concept of a gigantic mulberry tree to the east of the East China Sea faded with time, and gave birth to the vague notion of a mythical land existing at the far eastern end of the East China Sea, even farther east than the legendary Pénglái islands inhabited by the Daoist Immortals.
With the progress of navigation and of ship-based exploration, several islands to the east of China were called “Fúsāng” in the history of China, ranging from Japan to America to made-up stories to impress the Emperor.
Anyway, a series of recent articles on the internet have started mentioning the book The Mysteries of the Marco Polo Maps by Benjamin B. Olshin. Menzies-style, Prof. Olshin claims that the founder of the Yuán Dynasty entrusted the Venetian merchant cum explorer Marco Polo with a mission to Fúsāng, and that Marco Polo sailed along the northern coasts of East Asia up to Alaska (and back). According to some sources, the mission was funded by a southern noblewoman rather than by the emperor himself. Whichever the case, the book claims Marco Polo travelled all the way to the Aleutian Islands, where he met with the natives, to whom he delivered a message.
As with Menzies' book, I am not interested in the scientific value of Prof. Olshin's book (which is probably quite low) but in the crazy role-playing ideas it may provide.
Edit, May 2017: I had based the post above on articles read on the internet, and not on Prof. Olshin's book itself, which apparently does not actually endorse said theory (see comments section).