Gearwhore, I can't remember where I got the stones. I remember paying about $6-7 a piece for them. No, DMT does not sell that ceramic. I got it at the military sales store on base here in Germany, but you can probably find one at any sporting goods store.

Yes the different colors are different grits. They don't say what micron level they are, but the blue is coarse, the red is fine and the green is x-fine.

I just did a google shopping search for the mini-sharps. You can find them there for about $7.