I have not used either LinuxBIOS or fastboot, but I just looked thru the LinuxBIOS docs and it is my understanding that you can flash it yourself with a regular flash utility. I would be careful, though. If you flash this new BIOS and it's screws up your system, it's not clear to me how you would boot to reflash the old BIOS.
It looks like cwLinux offers preinstalled EPIA boards.
I supposed VIA's fastboot is safer, since it's from them, not sure how they would support it if you had a problem.