Don't reinvent the wheel
Just buy Mac Minis with OSX server preinstalled. OSX is based on FreeBSD
Apple (United Kingdom)
They even have the SSD drives you want as options, though personally I'd stay away from those. I don't believe the technology has advanced far enough for SSDs to be reliable enough yet in a business server envorinment (this is where I stand back and wait to be shouted down....) My comment is aimed at SSDs in general and not against Apple