Fantastic. The only problem is that I upgraded my OS recently and borked my OSX virtual machine. I'm going to have to find another way to test this myself. But as far as I can tell this is what I was looking for. I assume I can setup this environment once, and hold the git repo inside it. Then I can just pull the updates from my development machine and rebuild it and re-run the script to package it up...? There's already a Darwin branch in the makefile... I can just expand it as necessary.
By the way, how big is the final .app file? Compressed and uncompressed? Is it normal to distribute apps as zip files? If so, I guess the uncompressed size doesn't matter...
You'd have to modify the script a bit for what you want, especially if it's going to be in the makefile. I might play around with that later this week, I'll send you a pull request on github if I get any results.
The final app is about the same as my last version, 134.7MB for the actual app, 38.4MB zipped. Apps are almost always distributed in a zip or dmg, imo zip is better. Dmg doesn't really have any benefit other than being shiny.
Here's an app generated by the script:
http://goo.gl/GWeoO