I have some idea how to make "binary" packages, e.g. I repackage
sagemath into a PPA by simply unpacking the files, so nothing is really
built. There must be many *-doc packages in or *-data pacakges in debian
that will show you how to do this with best practice.
It looks like aptdaemon-data is really small and simple (apt-get source
aptdaemon-data) and a good example with a very simple rules file. It
uses files ending in .install in the debian directory to list files to
install. The rules file contains something like