Oneiric development has started and word it that Gnome 3 PPA will be included in the Ubuntu main repos unlike in Natty.
Thats some news to Gnome loyalists who have been using Ubuntu all this while! Due to the high priority of Unity in the Ubuntu 11.04 development cycle, the inclusion of GNOME3 into Ubuntu were postponed until 11.10, and Unity was shipped in Ubuntu 11.04 as a shell for GNOME2 instead. In 11.10 Moreover, since the Unity shell will run on the GNOME3 stack for 11.10, installing GNOME3 with GNOME Shell won’t affect the Unity desktop session and you will have a choice to boot into either Unity or GNOME Shell at the login screen.
For Appindicators a smart detection mechanism will be implemented to only show AppIndicators if a Unity desktop is detected. If instead vanilla GNOME is found it will fall back to the default upstream behaviour seamlessly.