In Spain it became "Tokyo Blues". I think probably the reason was that Norwegian Wood was not a so so so popular song over here for the mainstream public (excluding Beatles fans). It was not "Yellow Submarine" or "Hey Jude" level. I am pretty sure if the song from the novel was "Hey Jude" or even "Eleanor Rigby" they would have kept it.
Sure, it's not their biggest song. But from what I've seen, most of his novels have been translated with a relatively faithful title (say, "Kafka sur le rivage" for Kafka on the shore). It's only this one which gets a completely new title.
And I don't think it's even some bizarre copyright issue, as it could easily be translated in Spanish as "Bosque noruego", while the original song title, if translated, would be closer to "Madera de Noruga". It's not like he titled directly after the song in Japanese either...
