What is the tallest building that can possibly be built?

The Burj Khalifa at 2717 feet is the tallest building in the world, and it got me wondering- how high can you go? What is the practical limit for height on a man made structure? Is it feasable to construct a building 10,000 feet, or even one that reaches into outer space (62 miles)? At one point would even the most reinforced foundation be incapable of structural support?