I don't think the Kings really need a shotblocker. Raef LaFrentz is a good shotblocker from a stats perspective, but does he really make anyone think twice about penetrating on the Celtics? How much does one or two blocked shots really matter over the course of a game compared to the 15-20 shots someone like Duncan or Bosh is going to get? I'd much rather have someone who can play tough one on one defense in the post and make the Duncans and Boshs of the world miss shots than someone who is going to get a few flashy blocks.
What the Kings need is a good interior defender who is 6'11" or higher, someone who can take on the best 4 or 5 on a night in-night out basis. Brad Miller is not a good defender or rebounder, so let him guard the lesser of the opposing power forward or center, and let the dirty work 6'11" guy get the boards and play good defense. Whether or not that guy is a good shotblocker is kind of beside the point.
Get a good rebounder and someone who can defend and play a little offense. Kenny Thomas has shown what a difference a good rebounder makes in the lineup, but he's not big enough to be a good defender. Shelden Williams might pick up some blocks, but would you really want him guarding Duncan over the course of a game? Nope. I'll take one of the bigger guys, thank you very much.