FlyerTalk Evangelist
Join Date: Aug 2011
Location: Barcelona, London, on a plane
Programs: BA Silver, TK E+, AA PP, Hyatt Globalist, Marriott LT Plat, Hilton Diamond
Posts: 13,043
1 way won't be allowed on ANA. (it's not even allowed on ANA's own programme)
I suspect the mileage-based redemption levels work like ANA's own programme. You don't have to fly return, but you do have to return to the country of origin. So, in theory you could try to book a TYO-SFO, then add a ICN-TYO or something short like that (a flight you will conveniently "miss") to keep the total mileage as low as possible.
1 ways aren't allowed on any VS partners. Personally I would try to earn another 5000 miles and use 50000 to upgrade a return economy flight to London to Upper Class.
If you insist on economy, you're limited to the domestic stuff like US Airways (for a few more months), Hawaiian and Virgin America. Delta presumably will be coming some time in 2013/14...