There are precedents for all sorts of crazy lightsaber colors, actually:
There's even a precedent for a multi-colored "rainbow" blade.
I'm a pretty huge fan. I welcome crazy lightsaber colors - in fact, I think that's one of the best ways to continually expand itemization and differentiate more prestigious gear.
Personally, I would love a dual-rainbow bladed lightsaber - that would be so intense.
3 sith surround jedi consular. "We've got you now..." The moment draws close, the air grows cold. An orange, two red and a purple lightsaber ignite. Suddenly, a shining myriad of colors overwhelm the seriousness of the scene, burning the brains of the sith slowly to a mush as painfully as can be... One of them screams, "WHAT DOES IT MEAN?!" The other mutters something about trains always departing but never arriving, and the last one stabbed himself immediately with his lightsaber to avoid the visions he knew were coming.
Republic Wins, because the dark side cannot tolerate rainbow power. I should know.
I are jedi consular pony, my racial is the stare.