Dremel do one its brilliant, i also have a top of the range Bosch one (Dremel are owned by Bosch)
Bosch one is either on or off, Dremel one is variable and you can lock the spindle. it also has a brake so from full speed to stop is instant
http://www.dremel-direct.com/acatalo...iver_7.2v.html
yes im sponsored by em but they are bloody good
http://www.dremeleurope.com/specials...iver_en-gb.htm
same as james for me i bought a set of eds tools with the 1/4 drive hex to fit the driver, good and they have a longer shaft