I’ve always been a Murphden shipper, but I have always suspected (especially now since they have hooked up with so many books left) that Harry is “destined” to end up with Elaine. Which does not bode well for Murphy’s continued health.
I can see what you mean about Elaine, but my impression is her path post-Justin has diverged enough from Harry's that it isn't feasible for them to join up. Harry's path is well set - defender of Chicago from sundry nasties, Sidhe pacts not withstanding. We don't know a whole lot about Elaine's doings other than the appearances in Summer Knight/White Night and the mentions of collaboration on the Paranet, but I get the impression she's taking on a parallel role to Harry out west. Them joining together would pull one of them away from those established paths.
Oh, Murphy's into Harry. And vice versa. She'll be benched for the duration of her recovery, and her lapse in judgment with the Sword will be a psychological weight to carry, but after so long denying herself the chance with Harry, she's finally gotten the point of saying "Screw it, I want this." I fully expect they'll continue to be an item in Peace Talks.
Consequentially, I also fully expect her to snuff it at some point. Not because she "can't keep up". She and Marcone have proven that vanilla mortals can run the race even better than some of their supernatural cohorts. Because her story in relation to Harry's seems ultimately tragic. She'll age and die, while Harry has the potential (dumb mistakes not withstanding) to continue on for centuries. They'll hook up, and finally know a little reprieve, but then the Malevolence of Butcher will be roused against them, seeing the opportunity to extract further anguish from the wizard, and she will know surcease.
Honestly, I'm thinking post Murphy Harry will eventually realize that Molly doesn't wear training bras anymore, he'll stop repeating that specific phrase about training bras, and once he sheds the mantle of Winter Knight, and through one way or another, Molly somehow unbecomes Sidhe, they'll hook up. She's a practitioner, so the aging thing won't be an issue like with Murphy. Unlike Elaine, Molly's path has been inextricably linked with Harry's from childhood. From being influenced by him hanging out with her dad, to becoming his apprentice, to taking over his role during the Ghost Story hiatus of wizardly presence, to basically becoming another version of Harry in Cold Days prior to the Demonreach Faerie Lady Two-Step, to now effectively being one of his bosses. They're stuck together, one way or another.
Elaine fulfills the "old flame" archetype perfectly. She's out of the picture. Murphy is a romantically sympathetic ally, and a hardy one at that, but at heart, she's a fighter. She'll die that way, while Harry will go on. Molly was not, and currently is not a viable option, but her arc is rife with potential. Proven Guilty through Changes showed a potentially tragic character, but she survived the purgatory of Ghost Story and veritably thrived in Cold Days. Molly isn't a hardy fighter destined to go out in a blaze of glory. She's now a full wizard, and wizards have a habit of saying "Screw you, destiny, I'm rewriting you."