I'm not sure that Bert and Kathy will ever write "Head First Swing" or "Head First JavaFX", because I've never seen either of them discuss either topic. Bert is a Sheriff here, and I can't remember having seen him in the Swing / AWT forum at all since I became a staff member four years ago.
But why would you need Bert or Kathy to write these books? Head First
Servlets and
JSP is a good book, and it's written by others. There are many, many good books written by other authors.
That said, I do admit that I like Bert and Kathy's writing. I've read both the
SCJP 1.4 and SCJP 5.0 preparation guides (the latter for my SCJP 6 exam) and they've been great help.