In general, I like your approach - a lot.
One thing that annoyed me is the $self->self meme.
Me to, but like you I cannot see a way round it. I've just renamed it self_id in my local version.
That aside, here's my take on the base class - minus refaddr cause it doesn't work on 5.6.1.
Are you sure? It's basically the same implementation as the one here.
What I do is quite simple: store the hashref to the pad :-). Then all that AUTOLOAD has to do is trawl through the pad hashrefs and look for a matching attribute.
Falls over completely on 5.8.0. Probably because of this :-)
I like your use of an array to store the class hashes in. Makes the logic easier to understand. Might be a problem in the context of serialisation - since the position of the hash depends on the load order of the classes used by your application. You could always store a class->position mapping I guess.
I don't know if it's watertight, though. In particular, how well will it work if I call an accessor for a superclasses' field on a subclass?
There's the begining of a test suite in the version at http://www.quietstars.com/perl/ if you're interested.