Here it is, Gentoox Loader(info) with "NetBoot": a built in HTTP client. I wanted a Christmas Day release, but I guess I'll have to do with a Boxing Day release. There was a point where I thought this would never see the light of day due to various problems relating to LWIP.
This is only the beginning for NetBoot, more functionality is planned but I wanted to get an initial release out of the door so that people could test it. I've tried it myself numerous times from a local server and about 10 times from an SF server (the default server) and each and every time has worked (though I've probably just jynxed it). Read the manual included in the download for basic usage. For the real hackers out there, see this for details on how to boot your own packlet.
The only known bug with this so far is that downloading too fast can cause the client to lock up - if this happens, you may need to reboot.
*update* Gentoox Loader v6.01 has been released:
Another new feature: "Web Update". This downloads the latest version of Gentoox Loader from SourceForge and flashes it. This wont work until the file spreads to the HEAnet mirror.
Official Site: http://gentoox.shallax.com
Download v6.01: here