Or Harry as Pen Creed in "The Corinthian," overlooked by Sir Richard Snape even as they bond on a madcap quest across England ... oh wait, that's the Horcrux search! Complete with a fussy-girl Hermione and rough-and-ready Ron. Would have been so much better than the Trio's tent-camping-trip from hell.
Or Harry as Miss Taverner - the rich Miss Taverner - in Regency Buck, with the seemingly always-sneering Severus, Earl of Worth, actually hard in pursuit of the person plotting murder.
But what about Snarry versions? I'm blank at the moment. I'd love a Snarry "Sylvester," in which Harry is secretly the rising star of the Potions world, and "Sylvester" Snape -- even the name is appropriate, not to mention the eyebrows! -- the outraged Potions Master whose work has been skewered in the journals by the upstart friend of Ron (curricle accident=car into Whomping Willow? Bluff squire's family=Weasleys?)
In nearly every Heyer, I think, there are good country-squire Weasley-types (whether comic relief, or Good Yeoman Stock), and mincing Malfoy-type fops, for parody fun. And snarky romance, omg.