Joel Silver, who holded the rights to three Parker novels, hired Scott Smith, who wrote both the novel and the screenplay A Simple Plan, to script Backflash.
If you haven't seen A Simple Plan, it's a fantastic movie and Smith's screenplay was nominated for an Oscar. I haven't read the book yet (although I have it), but a friend tells me it is terrific as well.
The film got "Gibsonized" in the process, there is finally not a true-to-Parker film. A Simple Plan was a very dark film that made it to theatres intact, which gives me some hope. However, this must be weighed against the involvement of Mr. Silver, whose movies tend towards popcorn (admittedly pretty good popcorn) and who is also reputed to have given Mel Gibson a hand in castrating Payback.
And, of course, just because someone is writing a script does not mean that a movie will actually be made. However, I am no more optimistic that further movies based on Donald E,. Westlake's characters will be made, but hopefully it will at least some fun if not necessarily with Parker.