So you can serve a production site using Python's wsgiref and SimpleHTTPServer?

Servers do matter - memory usage, throughput, error rate, concurrent request handling etc. If the options are to use a faster server, or hunt down your code for bottlenecks, the choice is clear. Even if I modify my code to be faster, a faster server doesn't hurt.

This "benchmarks are useless" meme is overdone. "Hello World" benchmarks don't matter, but if a server is significantly faster on my real world application, why would that benchmark be meaningless for me?

Personally, I would like to know if this setup is available using gunicorn.

It would be very similar, you'd just need supervisord or something similar to run gunicorn for you. There is a pretty complete example of deploying gunicorn + nginx in the docs: http://gunicorn.org/deploy.html