Celebrim
Legend
I don't see how it could be accomplished using a rigid class system, but man do I love Skyrim where my greataxe-wielding orc in heavy dragonplate has two signature spells that he's practiced for specific situations.
I'll note that Skyrim is a solo game. I think the problem is less rigid class than it is in a cooperative game you'd be breaking the fundamental law of role-playing: "Thou shalt not be good at everything."
It's well known you can do point buy on a single player cRPG. I'll be more impressed if someone manages to make it work really well in a Diablo style 'real time table top' game or a WoW style MMORPG.
Feats or themes could work to emulate that, as could a mechanism where one could swap class features.
I think it would be hard in a Vancian system to produce a Skyrim like result. I'm not ready to abandon the Vancian spellcasting system for that cause, but you probably could do something like a fighter that can use 1 3rd and 1 4th level spell (at suitably high level) view a feat/perk system of some sort.
As far as a mechanism for swapping class features, I think you'd be better off implementing some sort of generalist class as the framework for that. An base example would be Monte's Aesthetic class from Arcana Evolved, but you could probably take the idea much farther if you borrowed some of 4e's systemization and applied it to a more 3e style approach.