Basically, I'm writing some tools in python. The goal is to get as close to a self-contained, one-step build as possible.
Currently, it's very much a work in progress and is very incomplete, but the idea is starting to take form. I like that the current code can create a create a macports tree, install dependencies, build the code, and create a bundle with one command.
The bundle is incomplete, and I haven't tried running it yet. I've only tested on my machine (OSX 10.9).
I haven't set up older versions yet, so I'm sure there lots of work related to getting older versions to work.
Credit to gtk-mac-bundler [1] for helping with the bundle creation (got this idea from GIMP).
[1]
https://github.com/jralls/gtk-mac-bundler