James Jordan's "Primeval Saints" has a few great points on the topic Gen. 9's account of naked Noah and Ham.
"(Ham's sin) consisted of something far more fundamental: rebellion against authority. This can be seen from the actions of Shem and Japheth. What they did was disigned to undo what Ham had done, and all they did was refuse to look upon their father's nakedness while upholding his office by robing him..."
He makes the point that Noah's robe is almost indubitably his robe of office, his mantle, his symbol of authority. Whether this is or no, clothing does represent one's vocational authority (a woman shall not wear that which pertaineth to a man, Elijah's mantle, David cutting the hem of Saul's robe, etc), and Shem and Japheth did cover their father with a robe in response to Ham, so his point is valid, regardless of which particular robe was used.
Jordan continues: "Ham 'saw the nakedness of his father'. How could he? His father was inside a tent--not just some little tee-pee but a real, house-sized tent. Ham had to invade Noah's privacy without permission. Ham was seeking to uncover a fault in his superior so that he could tear down his authority..."
A bit later: "Back in the garden, Satan had said to Adam and Eve, 'You can make yourselves gods by taking the forbidden fruit.' Satan now said to the heart of Ham, who repeated it to his brothers, 'You can make yourselves kings by stealing the robe of office'."
This point is dependent entirely upon the robe being the robe of office, which must be imported into the text. It is a sober importation, but not a necessary one, so I am rather hesitant to sell the house. It is an interesting point that I would hesitate to base anything on but would unhesitatingly publicize.
He makes a further comment: "Nor did they (Shem and Japheth) have to go to the trouble of putting the garment on their shoulders and walking backward. They did this for a symbolic reason. The shoulders are associated with pillars of support, and by putting the garment on their shoulders (instead of carrying it in their hands), they were symbolically upholding Noah's office. Since nakedness is associated with shame in fallen men (Gen. 2:25; 3:7), they refused to look at their father. They refused to shame or embarrass him in any way..."
All in all, pretty fascinating.