I see natural flavor, sodium caseinate, and milk protein isolate on  a few non-dairy creamers. What give non-dairy creamers milk like flavor? Can this be added successfully to almond milk (homemade)? 
I am not a nutmilk expert, but I do like milk more than most people I know, and I have dabbled in nutmilk. First thing, non-dairy creamers don't taste like cream. That's why some people will use them as sweeteners/flavor and add real cream as well. It's the best of both worlds if you take your cream with a little coffee. So saying, the only way to add milk flavor to your almond milk would be to add milk components. Lactose (sugar), whey and casein (proteins), butter fat, and more all contribute to the flavor of milk. The most noticeable factors affecting creaminess are going to be the proteins and fat. Proteins and fat are going to add texture as much as flavor though. You can recognize the significance of fat by itself within dairy milk. In my experience most people who actively like nutmilk tend to prefer skim, 1%, or 2% milk when they choose to drink it. But most people who prefer dairy milk will prefer whole milk, which is around 4%. If someone has a preference for skim or whole milk, they will likely find the other unpleasant, even though it's all the same animal's milk. And in light of that, if someone brings me a glass of milk that's watery instead of creamy, I'm not going to like it. It's not just the flavor, it's the texture. I've explored nutmilks because real milk is expensive and addictive (and I'm trying to lose weight. Why are cows do delicious?) Most of the nutmilks I have tried are lower fat, lower carb/sugar, and lower protein than cow milk. Many of them add sugar to improve the flavor. Many add stabilizer gums or emulsifiers to improve the texture. As far as creaminess goes, I would say the award goes to soy milk. It has higher fat and protein content compared to most nutmilks, but very little sugar. I only enjoy it with added sugar, which I try to avoid for personal reasons. Almond milk is the best compromise between natural sweetness and creamy flavor/texture in my opinion, and that's what I typically buy. The other nutmilks I've tried, while varying degrees of pleasant, really don't come close. However, I have to say I have not tried hemp milk or oat milk, but oat milk is getting a lot of hype for its creamy texture, and I would speculate it's due to the high fiber content. I can't talk much about it, but that might be worth looking into as well. So, how do you make your almond milk more creamy without adulterating it with actual dairy? My suggestion would be to increase the amount of almond solids that remain in your final product, and plan to shake vigorously before enjoying. This will also make it taste more like almonds, which is a good thing. If you explicitly want milk flavor as opposed to creaminess, then I'd suggest adding milk proteins (you should be able to get whey protein isolate pretty easily), lactose, or increasing the butter fat content with heavy cream.... But at that point, why not just buy regular milk? The final alternative is to do what the big brands do: add sugar and vanilla and don't think too hard about it. People tend to associate vanilla with creamy desserts pretty strongly in the US at least. Sugar tastes good, and vanilla is associated with creaminess, even if it's not creamy itself. How much attention do people actually pay to their glass of not-water anyway? 