Just read this, it says Apple will merge FreeBSD with Darwin and offer x64 and ARM versions for enterprise by 2014. Since FreeBSD has integrated a lot of Apple projects, especially clang in 9.0-RELEASE, it does seem kind of natural, but I didn't think this was in the roadmap for FreeBSD 10. Or could Apple just be taking advantage of the BSD license to fill in where Darwin might be a little thin? Kind of exciting if you think about it.