For the new site, I decided that a static site would actually work well and be simpler to develop against—the list of apps is a known quantity and we could figure out how to automatically rebuild the site when it changed. It also meant we could have more flexibility in hosting, including using the built-in GitHub Pages feature.
They detail how the project uses a Ruby script to collect the info and a Travis CI job to build the site. Pretty cool!
Not sure about appstream:// URLs, but yay static sites! 