I know several ways to conceal spellcasting, but I'm not really sure about where the crunch ends and the fluff begins, especially about including all the types of components into the concealing.
Out of my mind, there's...
- Disguise Spell (Complete Adventurer p.108) - it is a feat but the spell can't be recognized with spellcraft even if the enemies pass the Spot check.
- Conceal Spellcasting (Complete Scoundrel) - a skill trick whose mechanical effects are well described (no countering and no opportunity attacks)
- a new use of Sleight of Hand (Races of Stone) - this explicitly includes making the verbal components less obtrusive
- the metamagic feats Silent Spell, Still Spell and Eschew Materials
My own observations:
- Disguise Spell does not explicitly talk about hiding the verbal components. This is probably intended, since you're singing or dancing. Does this mean the other component is absent? (e.g. if you're singing, does the feat let you ignore somatic components? If you're dancing, does it let you ignore verbal components?)
- Does Conceal Spellcasting effectively conceal anything? My impression is that it just makes it impossible to counterspell or to react with an attack of opportunity, but everyone can see the caster is casting, and they can even see the somatic and hear the verbal components necessary for making Spellcraft checks and recognizing the spell.
- The SoH use from RoS is the most clear: it does not hide material components or focuses. Do the other two methods still require you to keep them in sight?
I am fully aware that D&D rules don't always match up with realism expectations, and that calling a feature "conceal spellcasting" does not mean "it has to work this way, otherwise it doesn't do what's written on the tin."