// XXX namespacing
Meteor._RemoteCollectionDriver = function (mongo_url) {
  var self = this;
  self.mongo = new Meteor._Mongo(mongo_url);
};

_.extend(Meteor._RemoteCollectionDriver.prototype, {
  open: function (name) {
    var self = this;
    var ret = {};
    _.each(
      ['find', 'findOne', 'insert', 'update', 'remove', '_ensureIndex',
       '_dropIndex'],
      function (m) {
        ret[m] = _.bind(self.mongo[m], self.mongo, name);
      });
    return ret;
  }
});

// singleton
// XXX kind of hacky
Meteor._RemoteCollectionDriver = new Meteor._RemoteCollectionDriver(process.env.MONGO_URL);

@@ -508,16 +508,294 @@
 f hacky%0A
+var mongoUrl = Meteor._get(__meteor_bootstrap__.deployConfig,%0A                           'packages', 'mongo-livedata', 'url');%0A// XXX bad error since it could also be set directly in METEOR_DEPLOY_CONFIG%0Aif (!mongoUrl)%0A  throw new Error(%22MONGO_URL must be set in environment%22);%0A
 Meteor._
@@ -858,28 +858,15 @@
 ver(
-process.env.MONGO_URL
+mongoUrl
 );%0A

Use deployConfig rather than $MONGO_URL in the mongo-livedata package.