Debian package building for single files or virtual packages?

[Nico Kadel-Garcia <nkadel@gmail.com>]

I'm facing some locally used tools that consist of only single files,
such as "mkrdns". I'd love to wrap it up in a .deb, but the dh-make
and related tools seem oriented around software that comes in tarballs
and has Makefile or autoconf or Makefile.PL already built into them.
And while amazingly expert at RPM, I'm relatively new to Debian and
haven't been building my own packages.

Is there a package building guideliine, or a good example, for a
package that is simply one important script or file from an upstream
source?