Per this Flyertalk thread and MightyTravels, you can book a one-way flight from New York-Milan for $130 including all taxes and fees on Alitalia. This deal is technically for two one-way flights the first being from New York-Milan and the return from Prague-Tokyo.
If you just wanted to go to Milan, you could “throw away” the second flight and book your own return back with miles.
However, if you did want to take both of these flights, you would be getting 2/3 of a round the world ticket and would just need a return from Tokyo, which you could also book on your preferred carrier using miles.
How to book:
You must book on Priceline, and choose a multi-city itinerary
I haven’t searched for other cities or dates, but wanted to post this ASAP.
Other dates for JFK-Milan that work are October 5, October 10, and October 20..
Update: still available in November, up to $160, just keep playing around with dates and cities on Priceline
Feel free to comment below if you can find other cities or dates that are working, but reminder to use Priceline to get these prices as booking on their own site would not work.
If anyone is thinking of heading over to Milan, now is the time!