Hypersmurf
Moderatarrrrh...
Anyway, having said that, I don't think it would be out of line to require a feat to treat a weapon as one catagory less than it is (making a scimitar a light weapon for a medium character, for example).
Well, there's already a feat that does something similar to that.
Monkey Grip in Sword and Fist lets you treat a two-handed weapon as a one-handed weapon... for a -2 penalty.
So using that logic, we would allow you to treat a one-handed weapon as a light weapon... for a -2 penalty.
-Hyp.