Hey, I just stumbled upon magpie after looking at your work on vigil! Clearly you are on the OneTruePath.
The major stumbling block that you have managed to avoid (consciously or not) is that you have not conflated the rampant confusion within OOP wrt inheritance. By throwing a ParentCollisionError you establish a direction of responsibility. Most everyone else, like Python, has been confusing the issue. C++ avoids it because it never tried to make "everything an object", and LISP never had the confusion because it keeps track of the everything through nested lists.
I would love to see you dovetail this work with vigil and make a true Python3k (which I mentioned to your vigil issues list). At some point, I hope the Python community will come along because 1) they know that there's an issue with Python 3.0, and 2) they eventually have to grapple with the issue latent between bytes and strings (which I tried uselessly to inform) which has to do with their implicit Object Model/Architecture.
Anyway, will be reading more. I recommend that you read about an effort by Mark Hahn called "Python with prototypes" or Prothon from 2004 because it looks that work would integrate nicely with magpie.
Cheers!
Mark Janssen
Gothenburg, Nebraska