Hi Niall
AFAIK, Juan is developing a new upgrade system (don't know if it will include scripts). Basically, you'll be able to select repository sources, and keep the PI platform updated, both the core application and modules. Along with the official sources ("stable"), one may include development repositories, to try new features. Also those repositories may point to 3rd party sources, allowing independent developers keed their own "packages".
It should be ready for 1.6.2, as it was previously scheduled for 1.6.1 but delayed because of some stability problems.