The closest we've got is the unofficial http://www.spellbookbuilder.com/. I think it's missing the latest Academy sets though (Druid, Necromancer, Elementalist and Monk).

Thank you for letting me know about that.

Without something like the Gatherer website or other software available for games like Magic: The Gathering to track inventory and create decks from their inventory, how do most people create decks in Mage Wars or keep track of their cards? Complex Excel files?