If you go the Dual-Class route be sure to consider the special abilities of each type of priest kit, too. Priests of Helm totally rock: the other two get powers which emulate 3rd level Mage spells (Lightning Bolt or Hold Undead) while Helmites get a 6th level power: True Sight! ... and a power which makes them a formidable fighter-replacement.
Imagine putting Tenser's Transformation + Improved Haste + Draw Upon Holy Might in your Sequencer, suiting up in some enchanted Full Plate and then using your Seeking Sword power! Six attacks per round isn't bad for a Cleric/Mage
-- Nifft