Rift Junkies' Mage Compendium has a Mage Gear and Stat Weighing spreadsheet among the links. Windows 7 Excel only.
http://www.riftjunkies.com/forums/showthread.php?1954-Mage-Compendium-Helpful-Links-for-Mages-Builds-Stat-Values
Click on the link and it will download.
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