I made this up yesterday and I'm really digging it. I don't think I've said here that I started Weight Watchers a couple months ago. I've lost 13 pounds so far. The eggnog latte at The Coffee Shop That Shall Not Be Named is 11 Weight Watchers points. For one grande! My drink is probably not even a full point since a whole cup of soy milk is 2 points.
It's not exactly the real thing, but it works for me. Here's the recipe:
generous splash soy milk (as much milk/cream as you may usually like in your coffee)
1 pk Splenda
splash vanilla extract
splash imitation rum extract