THEURGIC CREATIONIST [GENERAL]
You can create items using the knowledge gained from all of your spellcasting classes.
Prerequisites: Any item creation feat, able to cast spells from two different spell lists.
Benefit: When acquiring item creation feats or when creating magic items, you can add together the caster levels of all your spellcasting classes to determine your caster level. For example, a 1st-level bard/1st-level cleric/ 3rd-level wizard could gain Craft Wand and create magic items as a 5th-level caster.
Dragon Magazine #: 325 (A Surge of Theurgy – Feats that Combine Class Abilities)