As a Steampunk who is about to be a father, I am delighted to find this:
The only downside is, this is obviously a mock-up. There is, yet, no actual Steampunk-themed series of playsets produced by Lego.
But who knows… They have taken on Star Wars, maybe they branch out into Victorian Sci-Fi as well. In the meantime I do what every good and creative Steampunk should do: Dream!
PS: My regards to the artist!
EDIT at 21:58:
I was just corrected by my friend Piechur of Retrostacja & Steampunkopedia, there is actually official Steampunk-themed Lego, see the links in his comment to this entry. I am delighted!