So you're talking about something like SFO-LHR-NRT-SFO as one through trip?
That does not meet the definition of a
Star Alliance Round-the-World. Such a fare requires three stopovers of 24 hours or more.
Of course you could book such an itinerary somewhere (possibly for less cost than a Star RTW anyway), though it wouldn't be the Star Alliance RTW fare. The obvious question is why anyone would want to?
Though I admit that it would be fun to try to construct the fastest such possible itinerary just for fun.