The Spurs have two obvious needs (besides the health of the Big Three):
1. A big man who can play defense and rebound.
2. A permanent spot on the bench for Michael Finley.
Rasheed Wallace seems like a pipe dream to me. I find it hard to believe that Detroit couldn't get something better than Bonner, Hill, Mahinmi, Mason (these are the only four guys we would trade that anyone would want) and contract filler (especially when you consider that Detroit would have to cut guys to make room on their roster for our pu-pu platter).
So how about we go after someone who's actually available?
"Sacramento has been interested in me for a couple years, so maybe something can work out long-term there. If not, I'm an unrestricted free agent this summer, so I'm auditioning for other teams."
If he qualified, Gooden's rebound rate would be good for 18th in the NBA this season. I doubt he could pick up the entire idiosyncratic nature of Spurs' defense in three months, but his athletic ability alone would make him a better option than Oberto. (Also, I think he's do a better job against Lamar Odom than anyone we currently have.)
Drew Gooden's best attribute is that he's available for a song. Sacramento acquired him solely because of his expiring contract. I would bet the Spurs could get him for a second round pick. The salaries could be matched by signing Horry and sending him to Sacramento.
The obvious snag in all this is that is entails the Spurs taking on about 3 million in salary. Assuming there's a good chance he's healthy enough to play the rest of the season, I think it's worth a shot.