The recent issue of Dragon magazine got the old gears a-workin’ again. In the Oriental Adventures book we saw a number of kung-fu fighting styles which basically ammounted to a neato bonus feat that is the culmination of a long set of prerequisite abilities and feats.
Examples from popular fiction
The Suio School of swordplay included the famous Wave-slicing Stroke. Only those trained in this school of swordplay knew the technique, though its existence was widely known by swordfighters throughout the land.
The Yagyu Eight Fences technique was so jealously guarded that even extremely well-studied masters of combat knew no reliable counter for it.
The No-shadow-kick the feared maneuver of Wong Fei-hung, though his Drunken Style was even more fearful.
Should it be necessary to create a prestige class to allow for such abilities?
Though it would require some preparation and integration into the campaign world, fighting schools with special techniques can add a certain flair to a melee slugfest.
In the Forgotten Realms, Sembians and the folk of the Underdark have available to them a regional two-weapon fighting style. Dragon 301 introduces a number of add-on feats with a similar founding idea.
This can be applied in a broader sense than simply swordplay, though. Perhaps a Cleric who is indoctrinated into a particular sect within his church gains access to abilities that members of other sects may not receive.
Obyn, faithful of Allitur the god of propriety and Ethics has entertained the notion of joining a group known as Allitur’s Shield. This group of holy warriors includes Paladins but is mostly comprised of Clerics. Emphasizing Allitur’s desire that the good people of the world be protected from harm (as opposed to Allitur’s desire that the bad people of the world come to bad ends), the members of Allitur’s Shield have devised a number of means of dealing with supernatural evil that preys upon the weak.
Through rigorous discipline (the priests of Allitur are a lawful folk), zeal, and training, they have developed amongst themselves an ability to protect the weak from the supernatural influence of the undead. They are known to have struck down possessing spirits and save dthe innocent from the life-draining touch of incorporeal wraiths and horrifying ghosts.
In game terms, they have access to a specialized feat. By expending two turning attempts from the Cleric’s daily alottment, he may ward all non-evil creatures within 20 feat from ability damage or negative level infliction caused by any creature with the Undead descriptor.
This feat is only available to Clerics whose patron deity is Allitur and who have taken Protection as one of their domains. Furthermore the Cleric must already have the Iron Will and Enhanced Turning feats. Though usable by any Cleric that fits these criteria, only the Shield of Allitur actively teaches its members this feat: there are few else who have this ability
There is no particular reason that similar secret techniques couldn’t be devised that would apply to other (or any) class. Incorporating this into play would allow for some great customization of characters (PC and NPC alike) and add flavor to a campaign without all the work of creating an entire set of new prestige classes.