Just did a violin track with the ECM8000 and it turned out great. I positioned it about 8 feet in the air, pointing straight down at the carpet, and put the violinist under the mic.
But keep in mind that the specific violin and the player will make a huge difference. At times, I've positioned the mic off to one side, level with the body, pointed at the side of the violin. I've also had great results miking from below the violin as well.
Try to stay at least 18" away from the instrument, and just move the mic around till you find the best position.
Finally, if it's gonna fit in a rock track, just use one mic.
For a nice, spacious, warm violin sound, put the violinist in one corner of the room and position the mic about a 1/3rd of the way out into the room, slightly off the center line.