Besides the evaporated skim milk already mentioned, I've also seen plain, low-fat yogurt used as a substitute. I just did a google search this afternoon for "replace cream with", since I found an Atkins-style recipe that I wanted to try the SBD way. Since I usually have fat-free yogurt on hand, I was going to give it a try the next chance I get. Of course, it'll be in a recipe that I've never tried before, so I'll have nothing to compare it to! I'll have to rely on my taste buds alone!