Practically every Linux distribution is a source distribution.
Debian:
debcheckout zaptel
./debian/rules get-orig-source
patch and build.
or:
apt-get source zaptel
cd zaptel-1.4-whatever
debuild
CentOS/Fedora:
yum still misses a convinince "get source" . But you just grab a source rpm, extract it with rpmbuild -bp, see what you hve to fix, and then complete the cycle with rpm -ba zaptel.spec
And there are the less known ones: Gentoo is a mostly source-based distribution. While you could get along there with binary packages, rebuilding is the way of life there.
You could define there using build flags some common options. e.g. for Zaptel: if you want the bristuff modules (and if you want the florz patch on top of it), and what echo canceller to use.
Another distribution worth mentioning here is rPath. It is built not only on top of "sources" Rather, on top of a version control system. You can easily checkout various branches of the sources of the package and rebuild them to working conary packages.
And that was only a short list of Linux distributions. There are also the BSDs (Blue Screens of, err... derivatives of the Berkeley Software Dsitribution).