One thing I love about Linux, there's no end to "ways" to get things done. Here's a couple more. In /etc/passwd you will see your users listed beginning with 500, and up. If you change that to 0 when that person logs in, he will have root, but your root password will not have been revealed to him.
Another: chmod u+s will make the program RUN as root, no matter who started it. Niether of these are "safe", but there are always trade-offs of one kind or another, right?