That's an interesting technique -- I'm definitely adding it to my notes for the next time I give my inside-out objects talk.

One negative that I see is that it adds even more overhead to every property access -- instead of id being an alias to refaddr, this approach has a second function call and a comparison.

That means I'd never want to implement this unless it was really necessary. I certainly wouldn't use it for convenience to specify initializing values -- that's a high runtime cost for a one-time activity.