There are many suppliers now days, offering material close to this theme if not theme (era) specific. I've found that ALL OF IT is little more than a starter kit and you will need to make adjustments and tailor the items to meet your own needs, especially if you are going with a true Steampunk look (where's the Curator when you need him?)
The better but lesser known custom builders are in the U.S. and bare in mind that you want experience magic prop makers NOT artists making your effects. While I certain appreciate some of the items artists produce esthetically, magically speaking, at least when it comes to proper deception, much of this material tends to come up short. The Steampunk scene being rather picky when it comes to the quality and functionality of things, especially gadgets, which make up a big aspect around that sub-culture. So be picky! Shop around! Understand that you may have to toss a significant amount of cash at a piece before it fits your vision . . . a year or so back I purchased a Spirit Bell piece that ended up looking anything other than convincing. It took me another $150.00 and several months time working with local artists & crafts people, to correct the facade of the piece and make the gimmick far more difficult to detect. I have associates that do this with most everything they buy commercially whether it's from OUTLAW, Lebanon Circle, Rob Stanley, or Doug Higley for that matter (and Doug is one of the best!) .
Freddie Valentine can probably point you to others I'm not thinking of at the moment but one resource you may want to get your hands on is THE ARCANA OF BIZARRE MAGICK by Jim Magus (
http://www.lulu.com/shop/jim-magus/arcana-of-bizarre-magick/paperback/product-4379157.html)in that it not only lists sources but gives methods for aging props, etc. The Larry Baukin Anthology (
http://mevproshop.com/baukin-anthology.html) is likewise a great resource for routine ideas, especially if you are taking the NAZI style of Steampunk persona. Finally, there are resources (including makers) to be found at
http://www.dragonskull.co.uk/main_map.htm which is probably the best on-line resource on Bizarre Magick.