A mage, needing to work with forces that would normally destroy him, modified the Golem creation methods to build a construct. He imbued it with a limited intelligence, and the spell abilities required to work with raw elemental forces. I could see a construct looking a lot like the Dread Dormammu.
For more inspriration, see Doctor Strange comics, especially the "Strangers" story line.
One possible use would be for ultra-high level spell casting.
Another possible use: Charge constructs as you would a wand of fire, etc.
