h2o is cool too, I contributed to that project early this year for their OpenSSL/DHE parameter settings.
Re: How much time, hard to say from my perspective since a fair amount of rwasa's functionality resides in the library itself. Start to finish for all of the showcase pieces and the library (from 0 lines of code to release) took 13 months of my life :-)
I almost downvoted you by accident. Thankfully when I reloaded the arrows were still there. I reply think this "arrows to small" problem needs to be fixed. Although the refrain seems to be that it is not a problem: the community would vote such accidental downvotes back up
I've always wondered, how many man hours does writing a small web server like that take?