Read no more, I've got your answer.
From the Episode 2 Visual Dictionary, Pg. 62, under "Foundations", and I quote..
The Sith use syntheic lightsaber crystals, which generate a stronger blade when energized by the dark side of the force. Th advantage is slim, but the very appearance of a red blade is a symbol of hateful power.
You can draw your own conclusions from there, but there really isn't any solid evidence for Jedi lightsaber colors. Mace just got a purple one because Samuel L. Jackson wanted one, Padawan's have blue, Masters have green, etc. Even thats not true,