NTLite now supports simple post-setup automatic executions.
It can be used to integrate application installers, registry files, scripts (including powershell), or execute raw commands.
You can also provide switches, if available for a given installer, for completely silent install.

Offline, during image editing, the tool copies the integrated file to the ISO and executes at the end of setup, before users are created.
Online, during live installation editing, page is used as immediate batch execution.

Let me know on the forum or email if you would like to see more features added to the page.