Since the pipes run along the driveshaft and turn outward and then run along the fender and out the back most only give you chrome along the section at the fenders.
I've never seen one like you describe. However, I know someone that polished his stainless pipes and they were about as shiny as chrome when he got done. That might be what they did on the one you saw.
Here's a link to the thread on our club's forum:
SCMC Message Forum - Some teaser pics of my polished exhaust!!
and another thread:
SCMC Message Forum - Got some exhaust rust...