What you were probably missing are the unix domain sockets. My guess is that socket_pair wraps around those instead of the SysV IPC methods.

Why aren't you looking at somewhat smaller Web servers. Apache is pretty big and does a lot of in memory caching which is nice for a high-end server, but not really necessary for a server on a 200MHz cpu with a 10Base-T network connection. Maybe something like boa would be more useful, or if you don't need CGI scripts, just use the khttpd that hijack provides.