I've been seeing this Mace Windu argument all over the forums recently and I'm a little flabbergasted that someone hasn't spoken up to debunk this yet. Mace Windu might have been the only jedi in the Movies, but there were others. Take luke skywalker's wife Mara Jade for example, she had a purple lightsaber for a very long time before she met luke.
Referance: http://starwars.wikia.com/wiki/Mara_Jade_Skywalker
My reason for bringing this up is mainly this:
I totally understand people's arguments about the purple color crystal, the idea that it should be difficult or rare but still obtainable via more than one or two methods. HOWEVER, The way I see things is there aren't nearly enough colors to begin with. I don't think that the guys in the BioWare office should have to come up with ways to make purple more accessible, I think the color crystals need to be re-thought completely. There is plenty of information in the star wars universe to prove that there have been a wide various of colors used for a saber. However, at the end of the day I get that there may be many reasons why BioWare only chose the colors Blue, Green, Yellow, Orange, Red and Purple. Maybe its even some kind of weird licensing issue who knows.
At any rate, those are my two pennys take'em or leave'em