I've always been fond of the Howling Commandos, Stan and Jack's mid-60s creation that gave us a WWII "ethnic diversity squad" in the Mighty Marvel Manner. The Howlers have been confirmed to appear in the upcoming Captain America movie.
Now one way this gets interesting is that while the original Howlers used the traditional white guy Nick Fury, the movie will (presumably) use the Sam Jackson version. The classic Howlers were already notable in having an anachronistically integrated squad --- thanks to Private Gabe Jones (plus an Irish Catholic, a Jew, an Italian, a Kentuckian, a German, and a gay British guy). But having a black non-com in charge of a mostly white squad of Rangers? Even more anachronistic . . . but interesting.
In the comics, Stan and Jack eventually did a "modern" version of Nick Fury, a superspy Colonel 20 years post-war. Lee and Kirby were both WWII vets, and they were never shy about making middle-aged guys their leading men (Reed Richards, Ben Grimm, Dr. Strange).
But like most characters linked to WWII, Nick and the Howlers were gradually hit by the sliding timeline, the convention that comic book characters don't age in real time, but rather have all of their adventures squeezed into a 10 to 15 year period. For Richards and Grimm, this meant that by the late 70s, references to their service in WWII were dropped, and they were both stuck in somewhere in their early to mid 40s. For Nick Fury, it was either time to say he was a Vietnam vet or mention that he's been taking youth serum for several decades. Marvel went with the youth serum.
But unless I've missed it (and I don't miss this kind of thing), there has never been an explanation about the other Howlers --- several of whom appeared fairly regularly as SHIELD agents. In the late 70s, this just meant that they were a bit over the hill. I have a couple of "Captain America" comics from the early 80s in which they have one last adventure, most of them looking like very fit 60ish guys. But time marches on for these old soldiers as the war fades into history, so now, not only do we have Dum Dum Dugan still out there kicking ass at approximately 95 years old, but all of Dugan's adventures as a SHIELD agent happened sometime after his 80th birthday.