Crothian -- tell me if the below would be kind of what you mean.
I am in the process of sketching out a new campaign, with an intended audience of new-ish players. Thus, I don't want to dump my stack of 20+ D&D books on the table and say, "Build a PC," because they will be overwhelmed with options.
Instead, I plan to start them with the PHB only, and then gradually introduce new organizations (and affiliated PrC's), feats, spells, and expanded uses for skills into the adventures.
So for example in their 1st-level days, they might meet a Knight Protector of the Great Kingdom, who explains to them what his organization is all about, and if anyone is interested, tells them the requirements to join (in game terms, tells them the pre-reqs for the PrC).
Meanwhile, an enemy kobold sorcerer uses one of the spells from Complete Arcane against them. If the PCs ask about it, they can do some research (knowledge - arcana or role-playing) to find out about the spell and add it to their list of known spells.
As well, there is an enemy fighter-type with Monkey Grip (using an oversized weapon) and again, if the PCs ask, they can take the feat themselves the next time they get a feat.
That's my plan, anyway -- introduce all the crazy new options directly into the adventuring.