The person behind U2songs is reporting on another forum that there may still be a radio single, albeit released the same time as a surprise album launch.
What's cool is that, in addition to Streets, Moment of Surrender has also apparently been sent out to DJs for remixes.
I think this lends credence to the idea that what we've heard in the audiobook isn't reflective of what we'll hear on SoS (no way the audiobook versions of Streets or MoS would be radio singles).
Also, if they're considering it as a single, I imagine they've put a lot of effort into the new version of MoS, which really interests me. It's possibly my favourite U2 track of the 00s, and I love the idea of them having another go at it. Bono also said recently that it should've been the lead single from NLOTH, so maybe they'll try to 'redeem' it with SoS.