It’s possible. I’ve got a few ideas floating around; we’ll see if they coalesce into anything usable. I’d like to keep the first three books as a more-or-less self-contained trilogy, so if I do write another Mercury book, it will probably be a standalone novel featuring mostly new characters.
In the meantime, I’ve got several other projects in various stages of completion. My memoir, Not Living Up to My Potential, should be available in a couple of weeks. I’ve also decided to publish two other short ebooks: a collection of humor pieces called Monday Morning in the Mailroom of Good and Evil and a collection of short stories (which doesn’t yet have a title).
I’m also finishing up two novels: The Ray Gun Merchant, a space opera farce; and Schrodinger’s Gat, which I’m calling a “Quantum Physics Noir Thriller.”
So you may have to wait a bit for more Mercury, but you’ll have plenty of other stuff to read while you’re waiting. :)