What could be a suggestion for a monologue for Banquo's ghost in Macbeth?

In Macbeth, Lady Macbeth urges Macbeth to kill King Duncan, and despite his own misgivings, Macbeth ultimately commits the heinous crime. He relies on Lady Macbeth's absolute cruelty and his own "vaulting ambition" (I.vii.27) in killing Duncan. However, after killing Duncan, he no longer needs encouragement from Lady Macbeth; in fact, he ignores her pleas to "leave this" (III.ii.35) and pursues Banquo because of the witches' prophesy, that although Banquo will never be king,...

In Macbeth, Lady Macbeth urges Macbeth to kill King Duncan, and despite his own misgivings, Macbeth ultimately commits the heinous crime. He relies on Lady Macbeth's absolute cruelty and his own "vaulting ambition" (I.vii.27) in killing Duncan. However, after killing Duncan, he no longer needs encouragement from Lady Macbeth; in fact, he ignores her pleas to "leave this" (III.ii.35) and pursues Banquo because of the witches' prophesy, that although Banquo will never be king, his sons will be. After Banquo's death, Macbeth learns that Banquo's son Fleance is still alive and that causes him to behave irrationally.

In Act III, scene iv, the ghost appears and is seated in Macbeth's seat. Although no one else at the banquet is aware of the ghost, Macbeth can only focus on the fact that there is no room for him at the table as the ghost is in his seat. It is soon apparent that he is unwell and Lady Macbeth covers for his "fit." The ghost could speak at this point:

And so my lord, it seems I shall indeed be the father of kings.

The "weird women's" words ring true for me 

And Macbeth's "most foul" actions are his recompense. 

He will be discovered although self-discovery will no doubt elude him.

My conscience is clear and the sons of my sons will reward me most fruitfully.

Whilst Macbeth the host is driven mad by my presence,

His lady and his guests see only the beginnings

As his untruths, masked as truths reveal that

"The instruments of darkness" are at work but will never

Succeed except against an equally dark force...Macbeth himself.