This is less of a hint than a heads up. I was chatting with Rob Griffiths yesterday, the creator of this web site, wondering if one can partition a Fusion drive. It turns out that you can, but only the hard drive part of it. This, and many other questions, are addressed in this Apple technical note, which is worth reading. The Fusion drive is a new technology, and has certain limitations because of the way it works, but it can be useful to see what these limitations are.
Mac OS X Hints