Set the units to Metric and scale to 0.001 (milimeters) on the properties toolbar (scene)
create a torus (well its worse on that) then go show the normals and adjust their size by dragging the arrows - even with the shift key it isnt good. Can the size of the normal lines be dependant on the size of the face, ie %. This way it wont go nutty and gives visual priority to the larger faces. (sorry this is a bit of an idea besides a bug).
By the way, how can i always enable normals?