There's more steampunk on the way, starting with The Affair of the Chalk Cliffs, to be released in June. But a longer St. Ives novel is in the works too. Blaylock writes:

"A few years ago my interest in writing more Langdon St. Ives adventures was renewed.  I had never actually lost my taste for Victorian science fiction and adventure.  I still read and enjoyed it.  After Lord Kelvin's Machine, however, I got caught up in writing contemporary, southern California stories and novels, and they came to occupy virtually all of my writing energy.  Some time back I reread one of my favorite seafaring collections, a book by James Norman Hall, titled Dr. Dogbody's Leg, and an idea came to me for a "series" of St. Ives stories with a certain tone and structure.  Bill Schaffer at Subterranean Press leaned on me a little bit to quit talking about it and get started.  The result was "The Ebb Tide," which began as a short story but turned out to be a short novel.  I followed that some time later with "The Affair of the Chalk Cliffs." I find that I like writing stories of that length, which in fact are very difficult to publish, because they're far too long for magazine publication and too short to be of interest to commercial publishers.  You can spread yourself in ways that are impossible in a short story, but you can also plausibly maintain the pace of a short story, and the result can be read in a single sitting.  I've got several more ideas for similarly-told long novellas/short novels.   I'm working on a full-length steampunk novel, same cast of characters, but with a darker tone, although it's just getting underway."

In an interview in the Bulletin of the Science Fiction Writers of America, JPB talks about what steampunk is:

I often see steampunk categorized as dystopian fiction, for example, and often enough it is, but there’s no good reason that it should be. I’ve heard people insist that there must be steam involved, but that’s nonsense. People insist that the story must take place during Victoria’s reign, but that leaves out, say, The Anubis Gates, and most of Conan Doyle – one of my great inspirations – who arguably came into his own as an Edwardian rather than a Victorian, despite when he first began to publish. Wells, too, etc. Definitions are by definition exclusive rather than inclusive, which can be a detriment to one’s writing. For me, the great attraction of steampunk is that it allows for science and settings that are largely imaginary – space travel by gunpowder-driven engines, water-filled canals on Mars, lost cities in as yet unexplored mountains and jungles, backyard scientists pottering aboard oxygenation greenhouses in home-built spacecraft, etc. Also, it has the virtue of allowing for a language that’s richer than contemporary English. (I’ll suggest that steampunk must have that language in some incarnation.) And of course there’s an open invitation to work in an octopus or a squid, which certainly elevates any work of fiction.