Wow, I've missed a lot here.
As far as Theory 11 and the design goes, Alex mentioned (and I've seen elsewhere) that T11 is working more closely with the USPC these days. T11 redesigned the bicyclecards.com website, the USPC now sells Guardians under their own brand name in an unlimited (or at least seems to be unlimited) release as part of their regular product line, and this deck is probably another such collaboration - T11 designed it, gave it to USPC (after collecting a fee, of course) and they're running with the ball. That's my guess about why there's a T11 mention on the tuckbox.
What is steampunk, someone asked... It helps to remember what cyberpunk is, first. Early books written in the '80s by William Gibson, John Shirley, Bruce Sterling, Neal Stephenson and others posited a bleak future existence - a wide divide between the haves and the have-nots, the users and the used. Technology abounds, but it's often repurposed to do things it was never meant to do (in the spirit of old-school hacking). People living at the fringes of society, trying to claw their way through to survive to see another smog-covered sunset - that was cyberpunk. The movie that most epitomizes it would be Blade Runner. Fun things like genetic engineering and nanotech exist, but can go horribly wrong, oil is stupidly expensive, etc.
Now, imagine a scneario similar to this, but... Imagine that Charles Babbage's Difference Engine (long thought to be the world's first mechanical computer, though it was never built until about a century later) actually gets invented, developed, improved upon - and a steam-powered computer revolution takes place in sync with the steam era, the reign of Britain's Queen Victoria, the American Reconstruction and the Industrial Revolution. Countless possibilities can spring forth from these elements, and have from the numerous authors writing in the genre, one of the earliest being a collaboration by Gibson and Sterling titled, appropriately enough, "The Difference Engine".
Someone mentioned the TV program Wild, Wild West - that was probably the first steampunk fiction ever, a few decades before its time. The movie, while terrible on many levels, also demonstrated some steampunk elements. Airships rule the skies, steam-powered mechanical devices grow ever-more complex, even being developed into war machines by feuding European nations and American states. Some novels, like "Boneshaker", even throw in an element of the macabre - a catastrophic accident testing a machine meant to drill for gold in Alaska releases a noxious gas that turns the residents of a West Coast port city into shambling corpse-like zombies.
