This deal would make sense in a number of ways. Spotify has a devoted user base in Europe and good relations with labels. They have been negotiating hard in the US to bring Spotify to American users as well. An alliance here could help Google bypass all that pesky licensing negotiation and bring Android users an integrated music solution.
Neither company is saying a word, as expected. It speaks to the urgency of the situation that Google would go this route. Amazon has launched its Cloud Player service without label blessing, and Apple is reportedly closing in on releasing a cloud-based music service. What form do you think a Google/Spotify alliance would take?