Hi frano,
Rice cereal gave my ds horrible gas when we gave it to him! I think the only reason it's recommended as a first food is that it's very unlikely to be allergenic. However, neither are sweet potatoes, pears, etc. and I haven't had a problem with any of those.
Ds is also allergic to dairy, and the brand of cereal I use for him is called "Healthy Times". I'm in Canada, but it's an American brand. In addition to rice, there's oatmeal, barley, and wheat, and they are all dairy and soy free. I've also had good luck with the organic section in my grocery store.
Good luck!!
Vikki