Steve Sailer questions the idea of finding people too rich to bribe. I tend to agree and sum it up with a classic Mr. Burns quotation:
Homer: Mr. Burns, you’re the richest man in the world. You own everything!
Mr. Burns: Ah yes, but I’d give it all up for just a little bit more.
The fundamental problem here isn’t finding incorruptible people; that’s practically impossible. Instead, what they should aim to do is minimize the ability of the government to engage in acts of thievery and reduce its control. This makes it less valuable to bribe government officials, which means fewer government officials will receive bribes.