A 6 volt black and decker screwdriver has about that speed and a .25 inch hex output, however, it might have a bit too much torque, Also, it is large but most of the casing can be removed easily.
The price here is $22 but Last year I bought 3 for ~12 dollars each at target and ~$10 at walmart.
http://www.blackanddecker.com/power-tools/AS600.aspx