While I do like my current "pie piece" class system (Seems to be a big hit with players as well), as an alternate growth pattern I am really intrigued by this proposal put forth by A Paladin In Citadel. All characters begin as a thief and organically "grow" into another class.
I'd suggest you give it a read. No article of my own today as I'm still recouping from a trip to Disneyworld.
Warrior of the Steppes
5 hours ago