There is actually a book out there by William Gibson called The Difference Engine. It follows the alternative time line that maybe would have occurred if Babbages machine had been taken seriously. Ive looked at a few like these but to my shame havent bought them. I remember reading one about the crimean war where the British Empire had aquired atomic bombs or cannon shells thanks to the peculiar metal found in a meteor.
Im not sure if Bob Shaws "The Ragged Astronauts" trilogy could be classed as steampunk but they have the same feel.
Lol, I know I have probably mentioned this before but "The Adventures of Luther Arkwright" (a trilogy of graphic novels) and the sequel "Heart of empire" really have a fantastic steampunk feel. The book is concerned with alternate universes and a lot of the adventures take place on the surviving british empire timelines. Everything is so victorian yet modern. The main story takes place in an England where cromwell seized power but never lost it again. So the year is now 1984 and whats the world like?
Welcome to the forum Cephalpod, hope you like it here.