I wrote a flexible reverse proxy[0] using node.js, a year or so ago, and haven't missed the ability to serve static files directly - so I'm wondering what the use-case for that is? I guess proxying to rails, or similar?
I agree that static serving is not as interesting, but it is useful to be able to serve up a fail-whale page!
I'm sure that if I were to pimp the project properly then that would be a good thing to do, but half the fun of my proxy is to allow "interesting" rewrites, dynamically.
To benchmark I'd be too tempted try to game the results by doing a straight pass-through comparison to mod_proxy, nginx, etc. That would lose half of the appeal of the project in the first place.
and here is the benchmarks of it; https://gist.github.com/azer/5946227