I was recently introduced to the Philo Vance detective stories of S.S. Van Dine by an article about how T.S. Eliot (I think?) was a fan of detective fiction. I was surprised to learn that these stories, written pseudonymously by literary critic and NYC cultural avant-garde elite W.H. Wright, were all bestsellers at the time of publication, but have since faded so far from modern cultural awareness that I'd never heard of them in spite of having been close to several big-time golden age detective fiction fans. (If you read them, you'd probably also begin to feel you understand why they haven't stood the test of time as well as ACD, Christie, and Sayers, but I haven't quite applied myself to articulating my speculation yet.)
These novels feature a genius sleuth and a narrator-biographer sidekick, are set when they were written, in the 1920s-30s, and in some ways seem to bridge gaps between the above-mentioned writers, and to exist in conversation with them, in a fandomy, remixy way. (I also detect playful dialogue flourishes reminiscent of PG Wodehouse, although I have to note regretfully that the narrator is never Jeevesy.) But... gayer? I mean, of course, that foundation is unquestionably there in the rest of the genre, but here an overwhelming homosociality of the main cast combines with a definite coded gayness for the sleuth.
Sleuth Philo Vance, fundamentally a mixture made of largely Sherlock Holmes and Lord Peter Wimsey (maybe a dash of The Murders in the Rue Morgue, not least because of how his narrating biographer is handled), is coded gay in that early-20th-century asexual way. It's introduced with a pointed comment about a green carnation in the first scene with dialogue in the first novel, but never becomes actually relevant to the plot. He would read as asexual otherwise, but it isn't belabored or emphasized in contrast to anyone else, the way ACD did with Holmes, or Christie did with Poirot; it's just that sexuality would have been a complete non-issue if not for the green carnation remark and later, subtler hints. (Although ( spoiler )
And though I don't discern any coding in their characters, his entire cast of regulars - or trio of backup singers, you might say - are also bachelors, evidently leading existences free of any assumptions of heterosexuality and heteronormativity. The author-narrator, S.S. Van Dine, referred to casually as "Van" by Vance, is his live-in man of business or secretary or personal assistant, a lawyer by trade whom he picked up when they were together at Princeton, but who is now devoted full-time to his correspondence, financial affairs, and art collections.
Their connection to the world of police is through district attorney Markham and homicide detective Sergeant Heath. Markham is typically present with the narrator and Vance, either at home or dining out, for what seems like one meal in three and a portion of every day, even when they are at leisure, and the readers are treated to the narrator waxing poetic about the dynamics of Markham and Vance's relationship, history, feelings for each other, and the nature of their banter, which he seems to find mysterious or ineffable at times.
Heath is a friendly and respectful subordinate of Markham's and shares with him the role of unimaginative policemen who want to pursue the wrong suspect or clue and have to have everything explained to them by the genius, but they're also both friendly with Vance. Heath doesn't hang around with them in his off-hours, but he's still what one might call a Bachelor's Bachelor.
The upshot is a highly homosocial cast that I think would make a great candidate for an update into a modern queer female foursome. (They wouldn't really need to be solving mysteries: as mysteries go these are not remotely realistic anyway.) (Yes, this was one of those shower thoughts that starts with "Wouldn't I like X better if all the characters were female?" I don't know why I have this conversation with myself so much, because the answer is always yes, but imagining it is always fun anyway I guess.)
Just picture this:
1. The sybaritic gastronome genius classical translator, art historian and collector, unarmed fighter and dog breeder, a sharp-dressing perfectionist diva who makes a point of delivering all her genius statements as if she couldn't care less, when in fact she feels a deep empathy for everyone that she covers up with coolness. A huge vocabulary, excitable tangents about art, history, and cool science stuff that sounds like it comes from an encyclopedia, a tendency to occasionally quote literature in a foreign language and then pretend not to hear when people try to ask her wtf she's talking about.
2. The narrator of the books is so transparent you often forget he's there, so it's hard to tease out a characterization. But that mystique could be played with interestingly, like maybe the character could be a long-distance bff who is in communication via texts and Skype.
3. The genius's older, tolerant friend who is serious to a fault and acts like putting up with the tangents and flights of fancy is a chore, but secretly finds them charming, and also will always melt at any direct request. Responsible, busy, on time, could be conquering the entire world one-handed off-screen. Is getting gray hairs. Always protests that she's busy, but then the genius is like "But this new restaurant has KILLER (esoteric dish) that I want to feed you," and she's like, "Okay." Says things like, "It sounds like you can handle things," and then goes along anyway just because the genius wanted an audience for her brilliance. Obediently provides the appropriate straight-man line whenever needed, and also instantly and commandingly takes charge of any situation and/or group of people with sheer force of charisma.
4. Brash, confident, likable lady who is presentable but insists on dressing comfortably and less formally. Has been doing her job competently a while and knows everybody in the field, and is friendly with them. Great at delegation. Stubborn, never afraid of an exhausting, difficult or tedious task, patient. Has a fairly optimistic outlook and is fond of one-liners and snarky asides. Prone to getting fired with frustrated righteous anger; yells about it until requested to please tone it down because her vigor is exhausting. Literally always falls for (practical) jokes: will fall for anything. Has probably been flicked on the nose after looking down when asked "What's that on your shirt" hundreds, if not thousands of times.