With all sources available, you can hit +34 on a single check without even any items. Using the divine insight spell would give you +14. From there, you'd have 12 ranks (+26), +6 from synergies (+32) and only need a 14 charisma to hit +34.
Without divine insight, you could substitute a greater choker of eloquence giving you a +10 bonus (for only 24,000 gold) and a medal of gallantry, both from the Complete Adventurer, for a total of +12 from items, meaning you'd need an 18 charisma.