Similar to ANT, we'd like a mechanism whereby individuals can supply a separate file for build-time properties and these would replace variables during the compilation step.
A good use case for this might be the secret keys in ACS. We'd like to not store them in tiapp.xml, and instead have a separate build.properties file that contains the key/value pairs. This file would then get a .gitignore, so we don't accidentally check it into source control.
There would need to be some way to indicate which file contained the properties.