i've seen lots of people go from non-strategy to strategy, but it may be different depending on operating group. I've seen at least 5 people go into strategy at analyst and consultant level over the last 2 years or so. The best process to follow is usually to get yourself on a strategy project, show that you're really keen, speak to the right people, ask to be transferred, and if there's space and you're the right person it can work quite easily.