Great post. I give a lot of thought to this issue myself. IIRC, the romantic pairing in ELEANOR & PARK is between a 'short' guy and a girl whom society would see as 'large'. And given that book's bestseller status, that worked marvelously for many readers (and me).
I'm a 5' 10" woman who married a man one inch shorter than me. Totally surprised me.
And he's definitely been a keeper. As a teen, although I crushed on* guys of all height ranges, I told myself I could only ever be with a guy who was taller - I didn't want to feel or look like a 'giant' next to him (so, some of it was how I felt, and some of it was how society would see us). The biggest factor, I believe, was that I craved cuddling up to a man slightly taller and bigger. I longed to reach up and rest my arms against his neck and shoulders. I desired his power and strength - and I think that's what most cisgendered female, hetero romance readers crave, too, hence why the taller-male/smaller-female formula dominates in that genre. I'm trying to say I think it's more than a social construct only - I think it's instinctual for many people.
(*in thinking about this more deeply, it was easy to crush on a guy of any height due to his personality, but when I imagined us pairing off in an intimate way - kissing and more - I felt less attraction due to knowing I would feel awkwardly big)
In YA, it seems like you can get away with challenging that construct better in some kinds of books than in others. Some books are written to push boundaries - in fact, that seems to be what editors want nowadays. You see it most in the contemporary books today. But I will argue that there's another niche of YA books that cater to readers' fantasies, and that includes fantasies of the attractive couple (usually in the SFF line but can be in some YA contemporary, too, esp. in the romance genre) - and it would be harder to sell an unconventionally-paired couple in one of those books. So it's important to discern where your book falls, at least as an unknown author trying to break in. I'm all for challenging the status quo, but it's just much harder to do as an unknown.
Overall, as a writer, I'd like to give fair attention to romances between the taller girl and shorter guy, but it's a gamble.
I don't actually see many YA books with tall girls lamenting their height.
Fuchsia, if you or anyone else want to PM or rep me some titles, I'd be interested.