You can get ruby dust from redstone. Sounds hard, but really, there's a miriad of ways of getting the necessary amounts of redstone. From IC crops, through bees, to witch spawning.Still, what about the 100 stacks of rubies?
AFAIK the only way to get rubies is mining in deserts/hot biomes, and bees.
Any alternatives?
The nice thing is that you can use the mercury for your ore processing and the silicone for making the required circuits cheap.
I'm actually still suspecting greg came up with that particular centrifuge recipe with that in mind.