It's 99.8% guaranteed that the next Android OS update will bring multiple user profiles.
1) November, 2011
Google's Galaxy Nexus is released with Android OS 4.0, featuring the new Face Unlock functionality.
2) July, 2012
Half-implemented solution for multiple profiles is found in the Google code of Android 4.1 (with the feature disabled).
3) September, 2012
Google won a patent on the face-to-unlock functionality, first introduced in Android 4.0.
4) September, 2012
Google also wins a patent on multiple user support using face-to-unlock so each user can access their own homescreen on the same device based on the authenticated faces.
5) September, 2012 (very recently)
According to GSMarena.com, a tipster of theirs said the next Nexus will run 4.1.2 and will have a new "extra lockscreen functionality".