You mention the place at the end of the Commentary where Kinbote gives way to "the old, happy, heterosexual Russian." I've always thought there's a corresponding point near the end of Shade's poem. It comes here, in lines 923-930:

Now I shall speak of evil as none has
Spoken before. I loathe such things as jazz;
The white-hosed moron torturing a black
Bull, rayed with red; abstractist bric-a-brac;
Primitivist folk-masks; progressive schools;
Music in supermarkets; swimming pools;
Brutes, bores, class-conscious Philistines, Freud, Marx
Fake thinkers, puffed-up poets, frauds and sharks.

Everything after "I loathe" is not Shade but rather pure Nabokov--the VN who speaks in interviews and critical essays and for whom Humbert often provided the voice. But here it is such an obvious intrusion--as if Shade had stopped writing and a pre-cut set of pet peeves had been pasted in--that I assume it's VN's way of winking at us from behind the character he's created and is now making fun of. 

If, on the other hand, as many now are claiming, VN was trying in every line to write the best poem he could write, then these lines strike me as being among the weakest in the poem--weak because, if for no other reason, they're downright silly.

It's worth remembering that VN did not always describe the poem in the manner quoted in the article that Matt recently posted. In his letter to Rust Hills dated March 23, 1961, offering the poem to Esquire, he said: "If you want this poem despite its being rather racy and tricky, and unpleasant, and bizarre, I must ask you to publish all four cantos." Those are adjectives that some readers would prefer not to apply to Shade's poem, though they obviously apply to the Commentary and to many other of VN's works.

In any case, I was pleased to read Simon's query and your response. It's good to know that someone besides Dowling is pursuing this line of thought. The problem I've had when I've tried to follow it through is that I can't keep my "ahh" from collapsing, finally, into my "duh" and I find myself back where I started. It's too bad that Dowling himself, at least as far as I know, has never published his promised second paper on the subject. 

Jim Twiggs