I updated quickpkg with a few additions:
Scripts
You can now add pre- and postinstall scripts or an entire folder of scripts.
Ownership
Added an --ownership parameter that will be passed straight through to pkgbuild. Usually the default recommended will be what you want, but it is there if you need it.
Output
There is now a --output parameter that gives you more control over the location and name of the resulting package.
Bonus Trick
And as a neat trick, you can easily create a droplet for quickpkg with Automator by following the same instructions as for munkiimport in this article.