The way it would work is, I would create all the accounts myself and give each player temporary access. It would allow for "controlled" multi-accounts since I would know exactly who has access to each one and know who's to blame if an account does anything other than post in the mafia game. Normal users can't find posters' IP addresses, but Rolled could (so you'd have to trust him not to cheat). Also every account should appear with a USA flag if I register them.
The issues would be:
1. Lots of additional overhead for me
2. People who forgot to log in before posting in the thread, or log out before posting in a different thread.
3. Asking peppy to see if he is ok with it
The main advantage isn't actually the anonymity, it's the fact that I can add in unusual and unique roles that would normally be impossible or impractical.
And yeah I also thought of LadySuburu's idea, but that would be a whole lot of work (and would need 1 or more co-hosts to help and cover time zones). The game would also have to be slower in general (longer days) to account for non-instant forum posts.