The problem with posting information like that is that it IS illegal in alot of countries. Where is XDA hosted? Who owns and runs it and what country are they in?
In many countries posessing the tools to change and IMEI is also illegal. So if someone were to start posting information it might not be illegal for you readers in the US, but it sure would be to have the information here for anyone hosting/runing/administrationg the forum in a country that it is illegal.
Bottom line is, its not about you, its about the people who run this forum and the rules they have decided to operate it under. You might think its just anal posters shutting down IMEI questions, but in fact they're being helpful by efectivly saying 'its illegal in many countries so you wont find the answer here'. I'm sure if you search there's many threads about IMEI closed by mods.
Having said that, if you are looking for that kind of information you are probably better off asking one of the many 'unlockers'. They would know about the security used on the Nexus and if its at all possible - AND if not illegal for them to help you they might do.