Go to germany and accept their "citizenship" and you will be stateless.
You wont belong to a state but you will belong to a company in germany its the BRD GmbH.
What you are looking for as there are many diffrent status of a human is under law to be a human being.I know is sounds weired but as example in the US,UK,BRD people are treated in their law as goods.Some people are trying to get a natural person but thats also not 100% human under law and not stateless.Only human being under law is 100% human and doesnt need to be from a country.I know it all sounds very stupid but to answer your question you need to understand of your rights and i would recommend to make a research on laws from rome as they still are active.
If you are just looking for something to travel and not to change your personal status take a look here
http://www.youtube.com/watch?v=6PW34OD_geg
plz be aware its a "red" passport which means its not a 100% souvereign country/organisation