Vesper makes reference in CR to MI6 recruiting ex SAS types, and I have a sneaking remembrance that before CR came out the official website had some kind of mock file for Bond that said he was SAS.
I think he should always have been a naval commander at some point, which leaves the possibility that maybe he became SBS? (Special Boat Service in case anyone's wondering.)
As for the song, I think Adele would be great. The problem with her voice is, currently at least, not permanant, although if she isn't careful it might be--hence cancelling so many gigs.
I still think its a shame that Amy Winehouse was too screwed up to do the song for QoS, I'd have loved to have heard an Amy Winehouse Bond track.