Current Masters student, need advisor for PhD (no public announcements in the department)?
Rather than emailing lots of faculty asking for openings, I would recommend emailing a few faculty who seem most interesting to you asking for a discussion about the possibilities of joining their department.  The reason is that rather than just polling for openings, you want to get connected to the referral network (which your current professor appears unwilling or unable to do for you).  I would thus recommend approaching the discussion not as:


  Hi, can you hire me?


but instead as:


  Hi, I'd like to figure out whether my research interests and personality are a good match with you or others in the department.  If they are, can you hire me or else can you point me to somebody else who is likely to be interested in doing so?


This way, instead of asking a simple yes/no question, you are engaging the person in a way that may also lead you to good connections that you wouldn't have even thought of asking about.  By following the leads from such conversations, I think you are significantly more likely to find a good match than just by sending out polling emails.