To understand the inspiration for the object model see the original work done by Ian Piumarta.

Slides for the presentation given at DLS 2006
http://www.dynamic-languages-symposium.org/dls-06/program/media/IanPiumarta_2006_OpenExtensibleDynamicProgrammingSystems_Dls.pdf

Article published in the 1st International Workshop on Self-Sustaining Systems 2008
Open, Extensible Object Models
http://piumarta.com/software/cola/objmodel2.pdf

Extension proposed to support prototype-based object models
http://piumarta.com/software/cola/prototypes.html

Source code
http://www.piumarta.com/software/id-objmodel/

Presentation given at Standford, "Building your own dynamic language"

Duration: 1h15

The presentation covers more than just the aforementioned object model and provides an interesting point of view on every component of a dynamic language implementation.
http://www.youtube.com/watch?v=cn7kTPbW6QQ

Discussion about objects starts at 17m25 and ends roughly at 33m30.

Erick