6 days ago the platform/SDK.git was merged from tools v6. This may be an indication of a very soon release of SDK tools v6 and Android SDK 2.2 before the iPhone 4 OS release this summer.
The only side information I have at the moment which was oen of the comments in one my March posts is that more Android UI components have been refactored to have more public points of access for developers and that includes Android Tabs.
Side Note: Android SDK tools v6 has you download SDK addons via the avd manager, still no details of does that allow GoogleMaps to be enabled with those SDK emulator addons.
A Knol tracking the road-map has been posted.