We are interested in setting up a suite of custom Portal Admin settings that would be available to our custom modules and skins. We'd like these to be edited via extending the Portal Admin Settings module (versus creating a custom module), but are open to other alternatives.

We envision a custom "module" via Host Admin that allows us to setup the new Custom Setting Keys (and default values), probably would need a "replicate" button to "force" them into each portal, and then a Admin Settings "module" that would allow a portal to change their custom settings from the default. 

Are there any recommendations on the best path to accomplish this that would be relatively "outside" the DNN upgrade process, e.g. not having to download the source , extended it, and then compile our changes in and update our clients installs.