I had a very good friend who was a huge fan of soy products. Both she and her husband did not like regular milk, so they started buying soy and just fell in love with it.
It comes in flavors, vanilla, chocolate, etc as the other mom pointed out, and they also have a nice line of soy yogurts as well.
Another point I wanted to make was that cows milk has bigger proteins in it that are harder for babies to digest, which is why they stay on formula for awhile. At his age techinically he should be able to tolerate it, but again all kids are different and perhaps it's just being introduced a bit too early. If he really does not seem interested in the formula, maybe you can try natural juices. Most juices are made with only 10%, and have a ton of sugar in it, but Gerber has a good line of all natural juices as does juicy juice. And of course whatever other dairy you can actual get in him, cheese, yogurt, formula when he'll take it, just beware that yogurt can constipate!
Talk to your doctor too, see what he/she thinks, and don't ever forget that your his mom; you know that baby very well and if your doc can't give you an answer you like, you can always get a second, third, fourth opinion!!