Christian Neukirchen shows you how to create compact Scala applications for Android [1]. He explains how to reduce the footprint of the "hello world" demonstration application to just 20k from the 800k that you would get with the simplistic approach. Using his technique you can create compact Android applications in Scala.
Links:
[1] http://chneukirchen.org/blog/archive/2009/04/programming-for-android-with-scala.html