We will not see Android 5.0 Key Lime Pie on Google I/O 2013. We will stay on the Android 4 platform the whole year. And I actually thinks that is good. Better to fine tune what we have before moving to a complete new platform. We will see both Motorola X Phone and a Google Smartwatch though. At least that is what I believe. Watch this vlog for details.
Update: Some server logs on Android sites around the web shows both Nexus 4 and Nexus 7 devices running on Android 4.3 JWR23B. That is more proof that I am right that we won't see Key Lime Pie this year and only incremental updates of Jelly Bean. At least not on Google I/O. And as I said before, that is actually a good thing so that OEMs and developers get some breathing space.