That's a great looking light, but holy crap, the price! I thought you were exaggerating about how much it cost. How does a hanging light cost more than I'd dream of paying for a stove?

Wow. Those are pricey!
I found these two at PW Antique Lighting. The first one is still expensive, but 1/3 the price of the one you posted. The second is less.{{!gwi}}From GW Photos
{{!gwi}}From GW Photos

Let me know if this is the right track.

Look at Visual Comfort lighting for some very similar ones, and at Rejuvenation (semi-customizable) and Schoolhouse Electric for some that are significantly less expensive and similar in overall spirit.

Check out lights by Hi-Lite Manufacturing, completely generic name but some great lights, very good quality, made in California, and not too crazy on the prices -- especially compared to Urban Archaeology. This light is from their Milkman collection, shown here in a galvanized finish, but they do have a shiny one. Their version of polished chrome is painted aluminum. This light comes in 18" or 24" - as well as smaller sizes - for $171 and $448.20, respectively, on lightinguniverse.com. You might also check out their Harbor collection and their commercial offerings. Hi Lite has a website, but I don't think you can order directly from them -- but you can look around at their various offerings.
I bought a different style light made by them and was very, very happy.
You may know this, but this type of light is typically referred to as an industrial pendant and a similar look is nautical light. Both are very "in" right now, so I think Googling either term should get some good results. Have you tried ebay? I am often amazed at what I can find there. Other lighting websites -- shadesoflight.com, lumens.com, bellacor, wayair, even overstock. If you really want the cage over the lightbulb, add the word "vapor" to your search. Good luck!

Here's one at Modern Furniture Warehouse - it's similar in spirit at least. It's 20" wide like you want, and it's $590.

Here is a link that might be useful: 20-inch wide Metal Pendant Lamp