Quick project but I love how it turned out! I used a spare case fan and 12v wall wart I had lying around, and built a LM317 adjustable voltage regulator to control it. Built the whole thing into a cigar case picked up from Stanley Pappas, a great local cigar shop here in Denver.
It'll hold a 1" stir rod up to about 80% power, haven't tried anything larger. Looking forward to making a starter tomorrow for a dunkel, my first true lager!