One of the most famous models of the mid-1940s to early-1950s period was a strictly brought-up, super-smart gal from San Antonio, TX, Dorian Leigh, nee Dorian Leigh Parker (her dad made her drop the family name for work because he didn't approve of modeling - he came around on that later!). Dorian was graduated early from High School, and after her family moved to Queens, she did night classes at Rutgers in NJ to get her math and sciences up to scratch, then quickly earned a Mechanical Engineering degree from NYU. What would be a rare achievement even now, was almost unheard of for a young single mother (of two) in the 1940s. But after the career this led to (designing aircraft wing parts and working at Bell Labs) started to pall (Leigh claims she was underpaid and sexistly passed over for promotion), Dorian took up modeling. Starting relatively late, at 27, she was nonetheless an overnight sensation, appearing on the cover of Bazaar in her very first assignment. (Dorian's first agent advised her to tell editors that she was 19. It's unclear whether editors such as Diana Vreeland were really fooled or simply decided on the spot that Dorian had the goods and hence to play along/be discrete. Still, evidently Dorian was quite the smartie pixie, and was well-motivated to carry off the charade by having had a guts-full of unjust discrimination in previous jobs.) Leigh had countless lovers, married lots and dated more, was good pals with Truman Capote ('We had many long conversations in the early hours of the morning, and became good friends.'), and generally lived a pretty wild and interesting, party-hearty life. (Hyperbolic, Almodovar-worthy melodrama and tragedy would come later.) She had the candy store across the street from her Lexington Ave apartment take messages for her (pre-answering machines - although as the first page of Capote's Breakfast at Tiffany's reminds us, during WW2, private phones themselves were scarce, so that local stores/bars often ran informal phone services for regulars), and her better friends often entered her apartment via the fire escape. (Leigh specifically reports coming home to find Capote playing with her cats, having let himself in through the fire escape.) Capote's nick-name for Leigh was 'Happy-Go-Lucky'. She appears to have provided core ingredients for Capote's (avowedly syncretic) Holly Golightly character (Leigh reports that Capote later repeatedly greeted her as 'My Creation!'). This was discussed when Breakfast at Tiffany's was published in 1958, and again in Leigh's obits in 2008. Of course, Capote always averred that Holly's character had many sources, and indeed, all serious biographers trace some of Holly's details to Capote himself and to his mother (who, e.g., married a man who spent 14 months in Sing Sing, just like Sally Tomato, the gangster Holly visits every Thursday). Interestingly, however, Leigh doesn't appear in many standard accounts of what Capote termed 'the Holly Golightly sweepstakes', e.g., as summarized here.
Dorian's youngest sister, 17 years younger in fact, was Suzy Parker. By all accounts Suzy was the ugly duckling (sickly, asthmatic etc.) of the Parker gals (there were two other sisters - what are their stories I wonder?), but when she emerged swan-like as a teen, Dorian got her a top contract with the Ford agency sight unseen, and introduced her to superstar photographer, Richard Avedon. Suzy's career blew-up immediately so that Dorian almost literally passed the (emerging) supermodel baton to her sister in the early '50s.
Suzy's fast rise and muse-relationship with Avedon was the (only thinly disguised) basis for Jo Stockton (and esp. her close relationship with Astaire's Dick Avery) in Funny Face. Avedon, of course, did a bunch of photography for Funny Face, and Suzy has a small role in the film: she's the redhead model in the ad-like bits of Kay Thompson's wonderful 'Think Pink' number.
Amazingly, then, Audrey Hepburn got to be both Dorian's (partial) and Suzy's (full) screen avatars. Here's Audrey playing serious, unconcerned-with-appearances, bookseller-philosopher Jo, resenting the fashionistas invading her bookstore (I wonder if the featured fashionista is, as it were, 'doing' Dorian?) as Kay Thompson spots her potential (is this utterly ingenious shot with Audrey's eyeline physically possible?):
Apparently, all of this is very well known in NYC-centric, fashion/design worlds, but for a film buff it's kind of astonishing to learn that there is this infrastructure of non-Hollywood beauties underlying some of the most glamorous films of the period.
Suzy Parker herself had an indifferent, fitful film career, but she was in a terrific Twilight Zone episode, 'Number 12 Looks Just Like You', which is on youtube here. Dorian went on to open her own modeling agency in Paris (w/ branches in Hamburg and London). I've seen it reported (but have not been able to confirm) that she helped discover both Twiggy and the ultra-long/leggy Verushka. The latter is now remembered mainly from the sexiest (but also most Austin Powers-worthy?) scene in Antonioni's Blow Up:
It's striking how great the distance is from Dorian/Suzy to Verushka. Verushka could absolutely be on the catwalk today (where she'd probably dominate) or hanging on some contemporary rapper or rocker's arm (or doing smack with Kate Moss or...), whereas the Parker gals, like Kelly and Hepburn, are from a different world of romantic glamor. This is a version of the 'mind the gap' problem that's hurt Mad Men slightly for many viewers (myself included) as it's moved into the mid-'60s in Season 4. The informalized, anti-hierarchical world of the late '60s that Mad Men is now rocketing towards is just the world we still live in, whereas the early '60s is/was a slightly foreign country, one where we speak the language but where nothing means quite what it does at home. The just-slightly-alien is intensely alluring, just as Dorian and Suzy are here.
 In her 1980 auto-biog. The Girl who had Everything Dorian writes from the perspective of a late-in-life Born-Again evangelical Christian, eager to confess, officially regret, and accept the wages of all of her juiciest sins.