If you apply the Chain Spell metamamagic feat to the following spell, you could simultaneously trigger up to a maximum of 21 wands (when your caster level hits 20). Your character could also get some material to bind all the wands together like a package of fireworks... leveled at your enemy.
You could also do this with Scepters as described in Lost Empires of Faerun.
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Awaken from AfarEvocation
Level: Sor/Wiz 5, Clr 6, Drd 6
Components: V
Casting Time: 1 action
Range: Medium (100 ft. + 10 ft./level)
Target: One spell trigger activation item
Duration: Instantaneous
Saving Throw: None
Spell Resistance: No
An awaken from afar spell allows you to use a spell trigger item without actually touching the item. The item to be activated must be within the range of the awaken from afar spell, and it functions as though you yourself were triggering it from its current position. All other conditions, such as the requirement that you have the spell on your spell list or if the item's enchantment restricts its use to a particular race or individual, still apply. Both you and the item to be activated have to be on the same plane. The item cannot be in the possession of another creature at the time of activation, and it must be an item that you have previously triggered normally (in other words, without the aid of an awaken from afar spell.
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This spell is found at the following URL:
Wyrms of the North: Arveiaturace, "The White Wyrm"////////////////////////////
Or better yet, to perform the 21 Wand Salute, just carry a tube over your shoulder with a strap like a bazooka, with a bundle of wands secured inside and pointed towards the open end. Then you can lift it over your shoulder and level it at your enemy as you cast...
...then add little Unseen Seer (Hunter's Eye) and Arcane Trickster action to get some precision damage using the appropriate wands if you can pull it off.