I wouldn’t rule out version control (Github) yet. I think using a Github repository with a folder for each plugin is ideal for development. Also, Github has an API and has methods to grab raw files. I think you can place an XML document in the root of each plugin folder that has info on the plugin and the OSPi will just connect to repo and get folder list (aka plugin list) thats available. The user sees this picks the ones they want and OSPi just copies that portion of the repo into the plugins dir and does chmod a+x to the directory and reboot OSPi. This allows easy plugin install and easy development and management. No one has to worry about making packages, uploading them etc.
Ultimately, you will merge each request to the repo. Me, you and Ray can use an organization repo to manage the plugins (making the pull request process easier). Each developer would then submit their plugin via a pull request to a new directory in the main repo.