If you are willing to drive, you might try JetBlue out of Cleveland. They had some pretty decent fares the last time I looked. As you stated, the JB fares are not out yet but it may be worth waiting. They were around $550/pp for late fall of this year, Cleveland to SXM with a connection in Ft. Lauderdale. I just put in some random dates for Nov. and the lowest is around $650 currently. Good luck.

I fly out of Dayton OH and run into the same thing you do, lack of choices and exceedingly high fares.