Thanks for pointing that out. We minify production JS using Closure Compiler but sometimes that leaves room for improvement.
There's definitely a tradeoff between inlining JS and small images, but I think in our case it makes more sense to leave them external to leverage browser (and since we use a CDN for static content -- edge) caching.
I believe I tried to get ngx_pagespeed up and running when it was announced, but couldn't get it to compile from source. Sometimes (read: often) it sucks to be a FreeBSD user.