I am writing my dissertation on the conventions of soceity within shakespeares plays and for this chapter i am writing about the chain of being in macbeth, I have my starting point, (that he deviates from his proper place in society by attempting to move forward and in thus punished for it) yet I have still hit a road block in my work. Any help would be great :)
If I understand what you mean by "chain of being," you should certainly consider the witches in "Macbeth." Hecate scolds them for overstepping their position in Act III scene v:
How did you dare
To trade and traffic with Macbeth
In riddles and affairs of death;
And I, the mistress of your charms,
The close contriver of all harms,
Was never call'd to bear my part,
Or show the glory of our art?
If, too, you ascribe to the point of view which says the witches caused (inspired/motivated/prompted/instigated) Macbeth to his actions, they overstepped their place in the chain of being.
Are you concerned about your work on the effects of Macbeth's deviation from the Great Chain of Being or do you need other characters who stray?
If you are looking at lineage, I would look at Shakespeare's historical position in dealing with King James as his audience and legitimizing King James in England by his characterization of Banquo in the play. People in England were wary of King James taking the throne after Queen Elizabeth's death, and Shakespeare made sure to not make any waves in his depiction of James's ancestors.
If you add more about what you are looking to find, we could talk out some more aspects of the play, but I am not sure which direction you are going.