Mixing grammatical numbers "What pictures is it that you would like to see?"

Question

What pictures is it that you want to see?

This line reads fine to me, grammatical and natural, but I wonder if stylistically speaking I should try and get the grammatical numbers to match. Limiting my research tools to Google books instead of generic Google searches, I can't find much stuff that matches the pattern of "what PLURAL NOUN is it that..." but with a singular noun it is more common. Sentences like "What stuff is it that you are wondering about?" abound. So does my line work?

I also thought of changing "it" to its plural equivalent "them":

What pictures are them that you want to see?

But this line just sounds plain wrong. Something about "them" makes it out of place here.

What pictures are there that you want to see?

would be a good rewording of "Are there any pictures that you want to see?" and it is perfectly natural. But is the emphasis that comes with the "what is it that..." structure lost? Because this seems to no longer be a sentence with stress.

Note: I don't need simpler EFL/ESL-level rewrites such as "What pictures do you want to see?" That would be missing the point of this question and missing the emphatic tone that I intend for this line.

Answer 1

This line reads fine to me, grammatical and natural, but I wonder if stylistically speaking I should try and get the grammatical numbers to match.

As you suggest, it is more usual to match a plural subject with a plural subject complement:

What pictures are they that you want to see?

Still, because "they" is a less common dummy pronoun than "it"--especially in cleft constructions--this may sound somewhat awkward. You may, therefore, want to reword further.

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But this line just sounds plain wrong. Something about "them" makes it out of place here.

Your ear is correct. There is no reason for the objective form "them" in this sentence.

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But is the emphasis that comes with the "what is it that..." structure lost?

No, both sentences use cleft constructions and both retain the emphasis of that structure. You've simply changed "is it" to "are there", replacing one dummy pronoun ("it") with another ("there", if one considers it a pronoun).