Well hot damn! I'd love to join this one! So yeah I'll join but I think Axle is right, you'll probably have to wait until Doctor Who Mafia is done. And you'll have to redo sign-ups because technically you're supposed wait until everyone has joined and you have a couple reserve players before you PM roles. Just saying.
Once the Doctor Who Mafia has ended, a new sign-up thread will be created. The people who have already signed up will still posses their roles as before.