Yes, and something LIKE pnd would be great, and is certainly a thing to go for.
The .pra system (for Pyra)?
I would use a new extension and build a new system.
.pyr would be a better extension to use.
-God Ginrai
Why does everyone still use 3 character extensions? Just call it .pyra
In my opinion, the base system should just be some selection of Debian containing the most common and useful stuff. With some customized packages probably.
The PND-like system (let's call it libpyra and the files .pyra) would be an improved version of PND (better file format), with a list of dependencies in its metadata. At runtime and/or install time, the dependencies are checked and the missing stuff gets downloaded and installed.
To make a GINGE-like compatibility layer for Pandora PNDs would then be really easy: it would just be a nearly empty .pyra file that has everything in SuperZaxxon as dependencies, and all it has to do is execute the PND like on the Pandora.
Keep in mind that .pyra files will mostly be for new homebrew stuff. Ports of existing things will most likely already be in Debian. It only makes sense to re-package those as .pyra files if they are big games or something like that.
Ideally the Pyra repo takes in only recipes, and builds the .pyra files from that automatically (like Cloudef proposed). That way, it can also build .pnd files from the same input, auto-including the dependencies that are missing in SZ to the .pnd if possible. Or .deb files for various architectures (including Pyra, x86 debian, and Pandebian) that allow you to permanently install the application.
That would be the best way to make it easy to release cross-platform homebrew stuff that works on Pyra, Pandora and x86, without needing to package it yourself multiple times.