Plating can be a small fortune, especially if done right. It does look great and there is a "black" Linea up on the La Marzocco owners' site.

The stainless steel can be polished, brush finished, or even swirl finished (Paul Pratt did a great job of this on a Linea). The brush finish can be revitalized or perhaps even applied by hand using the proper finishing pads. I'm planning on restoring the brushed finish on my GS using 3M pads (search on "3M stainless steel finishing" for several references). You might contact a local s/s fabricator (often used for restaurant and other architectural details) to see if they can work your panels if you can't get what you want.

Powder coating is another option and is moderately priced. Quotes in San Francisco for my GS frame (two large and six small pieces) was between $225 and $415 for paint/rust removal, zinc-rich primer, and color coat. I ended up getting a great job done at the lower end of that range. There are all the RAL colors available, as well as "specials" like hammertone, fine textures, veined, and more.