That sounds pretty application specific. Why couldn't one just create the record array directly and then manage its membership in those cases?

```
var records = Ember.RecordArray.create();
...
var record = Model.mergeOrLoad(hash);
if (something or other) {
    records.pushObject(record);
}
```

The `something or other` above would need to be logic that can't be derived from model properties, otherwise a live FilteredRecordArray would work just fine.

I've yet to need that myself so far, but with using Pusher as well to get updated data, I want a live FilteredRecordArray to say always have all the comments for post_id X.

Do you have an example use case you could share?