Take Star Wars (the film) as an example. Luke is a farm boy. Lord of the Rings? Frodo is just an ordinary Hobbit living a peaceful life in idyllic surroundings. Often though, the call to adventure sounds, and before Joseph Campbell can write an influential book about it the hero is off a-questin'.
But the humble beginnings don't necessarily translate into the gameplay, does it? Especially for Saga Edition, which is the game I've been consistently playing for quite a few months now (thanks Hotfoot). Even a level 1 character is still pretty powerful. But take Luke from the beginning of Star Wars. Is he a Level 1 Scout as the CRB says he is, or is he a farmboy?
Can you start off as a non-heroic class and then bridge the gap into a heroic class when your 'call to adventure' sounds? Think of it like this, Luke is just a farmboy, he gets beaten up by Tusken Raiders, almost arrested by Stormtroopers and nearly shot by a shady bar patron - in all three instances, there was a high level heroic NPC to bail him out - and this continues up until they're all on the Death Star and Obi-wan runs off to sabotage the tractor beam, and Luke gets the bright idea to stage an impromptu prison break for Leia. (At which point, he might 'level up' to Scout)
I don't know how you'd do this in-game, but there might be a few ways. One way is to have a 0 level in the class you favour, where your abilities are rolled or bought normally but everything else is still up in the air. You're not good at anything but you're not supposed to be, because you haven't 'branched' out yet.
Another way is have a level in a non-heroic class, which then gets 'traded in' when your heroic path begins. So you start off as farmboy, and you have your abilities assigned and maybe skills (or maybe not, maybe this should depend on your int score - IE you only get skills if you would get bonus skills from having a high intelligence score), and probably no feats. Then as the story progresses, you can make a choice to go down a particular path - out of game, this means selecting a particular heroic class like a soldier, in game this might mean joining the Rebel Alliance and becoming that soldier.
In both the GM would probably need to run a particular scenario which allows the non-heroic character to become a hero without becoming a dice-magnet.
Non-heroic characters don't last long in these kind of epic stories. What to people think? Is it worth the effort of trying to recreate that heroic journey for RPGs? The Star Wars example might be challenging to pull off, after all Luke would be considered a 0th level Scout or a non-heroic Farmer in this alternative method, but what about Han and Chewie, who are a bit more experienced than Luke? Take the Lord of the Rings example instead. Frodo sets off on his adventure with Sam, and then Merry and Pippin. All four of these guys wouldn't be considered having a level in a heroic class, but by the end of the story, they're all basically high level adventurers. (Merry and Pippin survived on battlefields where more experienced soldiers fell. Merry himself helped kill the Witch King. And Frodo and Sam went to hell and back, almost literally given how hellish Mordor is) None of these characters really accomplished anything by themselves, other than running from the Black Riders until they met with Aragorn.
Note that I'm looking at the LotR from a particular angle. If you choose another then this idea doesn't necessarily work. After all, what if the PCs are Aragorn, Boromir, Gimli and Legolas, and the Hobbits are NPCs that are important to the story and need to be protected. Starting the 'game' at Rivendell as level 1 or higher classes like Fighter or Ranger would be appropriate.
If you read through my ramblings I applaud you.
