The bootstrapper works like a charm, thanks!
The PKGBUILD automation separates source downloading from the build functions, so I am manually moving over the already-downloaded translations repo and running the separate commands, instead of bootstrapping and relying on a mandatory internet connection during the build(). I can get away with the extra lines in an automated script.
But outside of a PKGBUILD this shortcut command will be very useful (to the limited crowd that would do a source install, of course).
Thanks for clarifying the necessary steps for me.
One last, minor nit: I noticed when using a --staging-root, there will probably
not be a "${staging_root}/lib/python2.7/site-packages/" directory (since python is not installed in the staging_root) so installing the environment module fails (unless it is manually created). Instead of offering a warning, shouldn't the setup create this directory?