I'm not sure what you mean by "fixing" javascript's OO implementation, but I guess you could have a look at qxoo, qooxdoo's oo engine re-packaged as a standalone project.
Thing is, that CoffeeScript solves the most common pain though (the *.prototype syntax), and the chasm between that and interfaces, singletons, private members, etc., might be too big for the standard use case.