Adopting some command-line build tools like Maven or Ant is definitely the right direction to go, it enables the possibilities of batching build process using Unix/Windows shell scripts.
Those minor customization you required are quite easy to achieve using maven-properties-plugin and android-maven-plugin together. android-maven-plugin support resource filtering. you can define your customized properties for each build cycle into several properties files, during the build process, android-maven-plugin can read those value from external properties file and substitute those value in AndroidManifest.xml and other resource file like res/values/strings.xml. android-maven-plugin also fully support Android Library Project, which let you extract/centralize common android code and manage all of them easily.
Suppose you want to build 5 apk distributions from a same Android Project with different package/app name, app icon and some resources in string.xml, you can create shell script run mvn deploy 5 time,with each time copy one of your customize.properties with proper other icon.png files into the project directory and overwrite the existing one. this gives you an end-to-end auto build batch processing that doesn't need any human interaction.
You can find a sample project MorseFlash examine the resource filtering used by android-maven-plugin.
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