Andy Rubin has said that they are developing functionality that allows a developer to design a tablet application which will work equally well on a phone. Something about designing an application as a series of panes. I believe it was in his "All Things D" talk, where he debuted the Motorola Xoom.

There's mention of it (multipane UIs) here: http://developer.android.com/sdk/android-3.0-highlights.html...