Highly recommend FPM for creating packages (deb, rpm, osx .pkg, tar) from gems, python modules, and pears.
Edit: found https://py2deb.readthedocs.org/en/latest/comparisons.html
that said, for python files and simple packages it works well enough!
One of the significant tradeoffs to this approach is you lose the carefully-crafted tree-of-dependencies that the distros favor, so it makes the package pretty much automatically unacceptable to package maintainers.
However, being able to have install instructions that amount to "yum/apt-get install <package>" is pretty great.
I am hoping for an app/container convergence at some point, but we might need to drop the fine-grained dependency dream and have them be more self-contained, like Mac OS X apps.
We also incorporate a set of meta packages which means we can have multiple codebase versions installed and switch the "active" one by installing the right version of the meta-package. There's also meta-packages for each service running off the same codebase, which deals with starting/stopping/etc.