It seems pretty clear from AMD roadmaps that there will be no new processors based on the Bulldozer architecture that the most recent FX processors use. Speculation: Mayyybe there will be one last FX83xx model to be made before production stops, and it would be 100 MHz higher than the FX-8370, but there has been no announcement, and so this is uncertain.
The FX branding has been used on and off since 2003, and so it is possible that there will be FX processors in the future, but they will not be like the Bulldozer architecture processors that are for sale now.