Well, I usually say "twenny" instead of "twenty" (not "twendy" even). I recently noticed that I never heard the same from any native english speakers during any talks I ever had with them.
Recently I had a brief search on the 'net and it seems that it is somehow okay to say "twenny", but it might look the least correct pronunciation for most of the people, or they might think you have strange accent, etc.
So, my question is, is there any good reference which clearly proves saying "twenny" instead of "twenty" is totally correct or wrong?
P.S. You're most welcome to write your very personal opinion if you don't know any good references.
I've already looked at the major dictionaries and didn't find any of them lists "twenny" in their pronunciation's section, however I'm sure that I didn't made that up, but I heard that while ago. Maybe in a movie, maybe from someone, and that's why I'm looking for the answer.