This is just my guess, since I'm not a plumber by trade.
The pipe that the shower head screws on to is threaded, and generally sticks out a little from the wall. I don't see why you couldn't buy a 90 degree pipe fitting that's threaded on the inside, and then buy a nipple (section of pipe threaded on both ends) to reattach your shower head to. I would go into a home improvement store with a big plumbing selection, and mock something up. Can't be more than $10 for a fitting and a nipple. The nipples are available in various lengths, from 2-6" IIRC.
Once it's the length you want, I don't know how it would look chromed.