Generally, having a magical wizard in your pocket would either be incredibly uncomfortable for one (or both) of you, or prohibitively expensive. Wizard upkeep costs an arm and a leg as it is, and with the money you'd spend on the reagents needed to concoct a shrinking potion, you could buy an entire mage. It's a pain, and usually not worth it.
There's is, however, a more humane, cost effective solution on the horizon. WizOrb, the pixelated, chiptuned indie block-breaking/RPG hybrid from Beatshapers and Tribute Games will smash through geometrically perfect arrangements of blocks and onto your friendly neighborhood PS3, PSP and/or Vita next month, when it launches as a $3.99 PlayStation Mini.