I've just cycled 2 tanks. One was a 46 gallon bow front. One was a 10 gallon that I set up as a quarantine tank. The 46 gallon tank took almost 6 months before I got a nitrate reading! The 10 gallon tank took only about 4 weeks. I know, I know...seems impossibly long doesn't it. I think that the point here is that no tanks are going to cycle the same way. I believe that we have to take in all sorts of environmental factors, and methods used. By the way....I have yet to have ever seen a nitrIte reading.
I will sit back and assume the patience position. Did you add plants during the cycle of either tank?