You might be hard pressed to construct one without getting a bit crazy. Most of the cost is going to be salaries of staff. At the extremes you have the Royal Family of England[1] ($43M) and Warren Buffet[2] (<.5M$).
The killer for entertainers and sports figures who blow through tons of money is keeping an entourage. There are probably tech figures who have one, but I don't know who they are.