Originally I thought that an alt druid would be a good candidate for a leprechaun mage. However, after reading the wikipedia page for leprechauns, I realized it doesn't fit. A leprechaun mage (if you want a more genuine leprechaun inspired by irish mythology, rather than just a magical caricature of the irish) would probably be more of a scavenger-trickster sort of playstyle. Probably trained in Mind and Level 1 War or something. since things like leather boots are war spells and leprechauns like to play pranks on people. However, they might put equipment on the enemy mage as well. I'm thinking he'd use level 1 command spells in a way meant to confuse and control the enemy.
Like say, "when this mage casts a command incantation on an enemy creature that would give a trait to that creature, it gives it the opposite trait (if one exists, if not, it takes the trait away instead)
So Charge would give the slow trait until end of round. Evade would remove elusive until end of round. Power Strike would give melee -2 until end of round. Etc.
http://en.wikipedia.org/wiki/Leprechaun