Literarily speaking, it's not just machinery out of time, but a conflict of man vs machine with man <3 machine, scientists far ahead of their times, a here-be-monsters/wonders attitudes, and a feeling that there are no limitations. There are very strict laws obeyed on the surface, but underneath? No laws at all, unless you get caught. Cherie Priest's "Boneshaker" contains all of those elements. James Blaylock's "Lord Kelvin's Machine" has some of it. Machinery, science, adventure all abound in Molly Brown's "The Selene Gardening Society", only her tale is lighted-hearted instead of grim. The RPG "Space 1889" has been a favorite game of mine since 1990. The original "Wild, Wild West" TV series is machinery, science, and adventure. There's not whole lot of fantasy in steampunk literature although it is common in steampunk culture. I think steampunk fantasy is ready to be explored.

I want to find out more about this challenge... I have a steampunk that I've started and want to finish. I agree that steampunk fantasy is ready to be exploited.

Hmm... unicorns and velocipedes? Do message me on Facebook where this conversation is continuing. I am very very interested -- and also in details about the challenge.