As a dozen pedants will now note, pipelining may not be the nicest thing to do to 'hefty' forking webservers like Apache. Whether or not IE does it already, and whether or not Netscape let you in the olden days.
Call this a "design flaw in the Internet," but they seem to have kept the default behavior for a reason.
As to tweaking the layout reflow timers and stuff, more power to you with that, I had mixed results the last time I played with it. :-)
