We can only hope he was joking suggesting Apple should move to Solaris on x86-64. I'm not sure how SPARC counts as a "volume platform" (whatever that means); maybe his spell checker accidently replaced a mis-spelling of "vacuum" platform, since everything I've read suggests their market is shrinking.
All will be revealed at the keynote, and no one cares what I think. But here's an alternative.
Your experiments with Darwin have hopefully started to show you how innovative systems architectures can provide better performance, security and stability.
We've recently shown that Itanium is an excellent architecture for implementing these systems. Why not have a look at some of the latest generation systems and we'll build something that is ready to push us forward for another twenty years or so.
If people think Xen is cool, wait till they see what you'll be able to do. And how much faster and cleaner you'll do it. Oh, and just like SPARC we can switch between big and little endian mode. Better still, the technology exists to run those PowerPC binaries directly. Not only that; we're a first class target for Linux development which means you've got an ecosystem to grow in. As you might say yourself ... "think about it"!