According to http://en.wikipedia.org/wiki/Kobe_beef , it's being done already. The marbling of the fat isn't due to the booze alone. The combination of alcohol and massages is supposed to keep the cows nice and relaxed which is supposed to lead to the distinctive texture of the meat. Good meat comes from happy cows?

On the topic of ground meat, if you buy it from your local supermarket, the packages are labeled with the lean/fat ratio. To my knowledge, 80/20 is supposed to be a good for burgers. Your average cut of Kobe meat probably has a lot more fat than that, but you could probably bring it down if you blended it with leaner meat. But what's the point in that?