Is it possible for Avian to support the java.awt.Robot class? (http://docs.oracle.com/javase/6/docs/api/java/awt/Robot.html)
Would be superb in terms of cross platform automation use, currently the only other cross OS compatible solutions are to use Lazarus/Free Pascal or full blown Java VM.
You can use Avian with the OpenJDK class library to produce a standalone executable, in which case java.awt.Robot should work. ProGuard could help to keep the size down.
It would also be possible to implement java.awt.Robot from scratch and add it to Avian's class library. That would give you a smaller executable but require significant effort and a lot of platform-specific code.
The best choice depends on what aspect(s) of a "full blown Java VM" you're trying to avoid: e.g. size, installation complexity, licensing issues, etc.