Willbern, David. "Phantasmagoric Macbeth."
English Literary Renaissance 16.2 (Autumn 1986): 520-549.

Thesis: Willbern begins his essay with a big promise:

In place of conventional analysis that traversed the two-dimensional plot of the play, Knight [a literary critic] called for a three-dimensional mapping of its irrational dreamscape. In this essay I will sketch such a map, through a style of imagining Macbeth that is vivid and visceral, psychoanalytic and phantasmagoric.  (520)
He keeps only one part of the promise. The essay is not vivid, nor visceral, or phantasmagoric, but it is psychoanalytic. He treats the play as a tangled dream, in which everything is symbolic of one or more (more often, more than one) psychological impulse or process.

Duncan's murder, Willbern writes, may be interpreted as "symbolic patricide" (521), or as "symbolic matricide" (522), and "Combining these patricidal and matricidal readings suggests King Duncan as a magical composite parent, both father and mother; his murder then becomes a complete parricide" (523). And there's even another interpretation of the killing of the king:

The most intriguing psychoanalytic reconstruction, and the most complex, is of the regicide as symbolic infanticide. In this interpretation, the King becomes a satiated then victimized infant. For instance, as Duncan prepares to visit Inverness, he savors his "plenteous joys, / Wanton in fulness," and announces that Macbeth is "full so valiant, . . . am fed; / It is a banquet to me" (1.4.33-34; 54-56). Together Duncan and Banquo describe the Macbeths' home: "This castle hath a pleasant seat; the air / Nimbly and sweetly recommends itself / Unto my gentle senses.  . . . Heaven's breath / Smells wooingly here " (1.6.1-10). Their references to beds and procreant cradles and breeding impinge immediately on the entrance of Lady Macbeth, who has just warned that "the raven himself is hoarse, / That croaks the fatal entrance of Duncan / Under my battlements" (1.5.38-40). The imagery evokes a typically Shakespearean fusion of architecture and anatomy: a fusion furthered by Duncan's conversation with Banquo. Inverness is the scene of hospitality and hell, and the castle becomes (fantastically) Lady Macbeth's body, the battlements her transfigured woman's breasts. The locus of gratified desire and gratuitous death is the same: a pattern repeated in Duncan's bed (the place of healing rest and fatal assault), and in the witches' cauldron (where ministry and murther coalesce).  (524)
And so it goes. Willbern offers similar interpretations of other aspects of the play and concludes on a mystical note; he writes that for the audience "to enter a realm of desire in which 'becoming' and 'destruction,' generativity and degeneration, is and is not, forge their disturbing co-existence: such is the potential experience of Macbeth" (549).

Bottom Line: Willbern shows that if you ignore the plot, any interpretation is possible.