There is no project... just experimentation with LevelDB. All of those solutions that you provided require an installation of CouchDB on the server side. Therefore, a bit out of scope of building a quick hacky Firebase clone using LevelDB modules.
Edit: I see what you mean: Pouchdb-server [1] is a couchdb-compatible server that speaks the same sync protocol. If you don't want to install it, you can work with any hosted couchdb-speaking cloud instance, such as iriscouch [2] or cloudant [3]
[0] http://pouchdb.com/getting-started.html