An email arrived at Phoronix this morning that the ArchBSD.net web-site is now online. This new site looks just like ArchLinux.org, but Linux references are replaced by BSD. Right now there isn't too much information available on Arch BSD, but the news from this week states that a test ISO should be available shortly.
While information is limited, it doesn't appear to be a very haphazard idea. There's references to Arch BSD going back to mid-2012 in the Arch Linux forum that appear to be by the same developer.
It appears the Arch BSD concept began in June of last year. As far as why Arch Linux is being gutted of the Linux kernel and replaced by FreeBSD, the developer wrote, "Why would I do this? If like me, you enjoy FreeBSD and love it, but also like the philosophy behind Arch Linux, which is a fast, lightweight, optimized distro, I figured why not combine the both. Even tho you could just do it on FreeBSD using the ports, not everyone wants to compile."
There is a GitHub repository that seems to be by the same developer and for his operating system attempt. "Welcome to the ArchBSD project, currently work is still under process and there is still quite a bit of work to be done. However I am approaching to release a test ISO soon after months of work. The ArchBSD project focuses on using ArchLinux package manager on the FreeBSD distribution, to provide optimised, up to date package for FreeBSD users. This project has also chose to use Gentoo's OpenRC init system as opposed to the default init system used by FreeBSD. Which personally I think provide a benfit of speeds and features otherwise not present in the current RC scripts."
The most recent activity in that Arch BSD script repository is just over one week old and has lineage going back to mind-June of 2012.
For those curious about the differences between Arch and FreeBSD, there's this Wiki comparison page written from the perspective of Arch.
The Arch BSD concept is very similar to that of Debian GNU/kFreeBSD, the pairing of the Debian GNU user-land with the FreeBSD kernel. With the last release of Debian (Squeeze), the Debian GNU/kFreeBSD port reached a rather usable state and continues to progress nicely. Debian Wheezy is also much improved for GNU/kFreeBSD.
Another similar attempt has been Gentoo/FreeBSD to have a FreeBSD-based Gentoo operating system, but that effort really hasn't gotten off the ground compared to Debian's work. "Gentoo/FreeBSD (or Gentoo/FBSD, or G/FBSD) is an effort to create a complete FreeBSD-based Gentoo system, sharing the complete administration facilities of Gentoo with the reliability of the FreeBSD kernel and userland. An experimental, yet incomplete release have been done, and it's possible to install Gentoo/FreeBSD following the install guide. This project is still in its infancy. If you are interested in working on it, please send an email to the Gentoo/*BSD team."