Amechra: if your post was directed to me, I said that rods were more powerful versions of wands, not the reverse.

First, the feat is Double Wand Wielder from Complete Arcane and it allows you to use 2 wands though the 2nd wand expends 2 charges instead of 1.

Second, Wand Mastery feat from Eberron Campaign Setting allows you to increase the DC of your wands by 2 and increases their effective caster level by 2.

Wand Modulation is a spell (also from Eberron Campaign setting) that allows you to temporarily change spell in your wand to a different lower level one.

Scepters are from Lost Empires of Faerūn and require the Craft Scepter feat. Scepters got no love after that book. There's not a single scepter in the Magic Item Compendium.

Eternal wands are also from Eberron Campaign setting.
An eternal wand holds an arcane spell of 3rd level or lower with a maximum caster level of 6th. Unlike a traditional wand that holds 50 charges, an eternal wand allows any character who can cast arcane spells to use the spell contained in it twice per day.
You also need the Craft Wondrous Item feat to make these rather than the Craft Wand feat.

Debby