Gpelpel, I can't answer your question, as I'm not an expert. In the case of the Wabi bike, I'm not sure "brushed" is the correct term; it's advertised as a polished frame. Brushing leaves a more matt-like appearance.

I doubt, though, that the tubes come polished by some method from the manufacturing process itself. I'm guessing you could strip down your own bike and come up with a polished version.

In fact, you can ask the man who ordered up the manufacture of my polished bike, Richard Snook: contact@wabicycles.com. I know he'd be glad to answer your question, if someone here doesn't answer it first.

Or there's this, from a web page about polished metals:

"#8 SUPER MIRROR (also called non-directional mirror)

A highly specialized finish produced by circular oscillating buffing, initially with abrasive compounds, followed by a rouge like compound. The surface is completely free of grit lines."