Here are the Armani Bronzing Powders that I own. I believe all have either been limited edition or discontinued except for 1, 2, and 5. Nordstrom.com & Neimanmarcus.com still have #8 (which I do not own). Often times counters will still have stock of discontinued colors.
Every summer, Armani releases a collection they call "bronze mania" many times the collection will include a two tiered palette with eyeshadows or highlighter on top and bronzer on the bottom. Here are a few previously released limited edition palettes compared to the individual shades.
* Please note that this collection is not comprehensive of all products that have been released, only the ones I own.
Some more bronzer posts and comparisons can be seen HERE.