there are at least a few big companies already doing virtualization with android to separate business and personal modes so that corporate email and other apps can be quarantined off with a secure password, leaving personal email and games to run in a separate environment that may not require as much security to unlock.

presumably the same technology could be used to provide "normal" and guest environments.

https://www.youtube.com/watch?v=ydXJjCN2G-A