We talked about doing this at my last job, and never did. When I read "...gives a small group of employees 2 weeks or ‘a limited amount of time’ to work on a project outside of their normal responsibilities at Apple", it made me think of the same attitude- the inability to commit to full-on innovation and creativity. Tim Cook, you are a great CEO, but you don't know how to take sufficient risk to get the reward. Everyone should get the 20% time. Don't do anything half-assed, ever. Even better would be to 1-up Google and say that you don't give a flying fuck what your employees do as long as they are innovating for the company and doing what they love to make people's lives better.
This is an awesome post. I award you with an Indignation: http://www.youtube.com/watch?v=EtCiP8B2xpc#t=7s