I like the Makita 6501 1/4" drill. Here is one source, so you can see it
http://www.toolbarn.com/product/makita/6501/

Unlike the right angle drills that seem to wear out certain bearings, this
is a durable drill. For sanding the bottom of bowls, I can hold it in one
hand by the barrel with the speed locked on. It is not reversible. If
reversibility is essential for you, maybe you could try a router speed
controller. I tried a 3/8" drill and it felt huge and awkward for this job.