I'm with timvp on this one. Nothing should supersede winning a championship. Not hoping to sign a post deadline buyout (Maggette, Pryzbilla, McRoberts, Telfair and Bell, come to mind as potential options) and not acquiring a trade exception to increase the amount of salary they can take on in a draft night trade. If they can get something decent, then by all means they should pull the trigger, but I wouldn't just trade him for the sake of it at this point.
I know you're thinking the Spurs don't need Blair to win a championship . . . but they might. There could come a few games where where one of the top three is in early and/or constant foul trouble and the match-ups don't allow for going small or where one of them is injured and if Blair is traded and they don't sign a McRoberts or whoever to replace him, then the options are Bonner (need I say more?) or Baynes. Call this a hasty assessment if you wish, but I can't imagine him being a contributor in a playoff game this season.
Richie, that's not a bad idea, but if someone in that range were willing to do that, a trade would be done by now.