When I made this vehicle for the Vehicles group project I took one apart. There are a ton of pieces for it once it is disassembled.
http://www.joecustoms.com/customs/custo ... motherbirdTypically I do the same thing you do, take out everything I see, but then I also try to pull it apart and see if I can find exactly where it is sticking. Most times there is a screw under a sticker or inside. On this helicopter I see to remember either the section of the front rotor was clicked into the roof or there was a screw only accessible from inside. Sorry that isn't much help but it has been a few years.