Build it from source. You need a debian/ubuntu system to do this. (Get a free amazon ec2 or something). Once you download from the git repo, you run this command:
sudo python scripts/build.py setup-schroot-centos6
And then:
python scripts/build.py centos6-amd64
If you're not on a debian-based system, you'll get "This can only be run on a Debian/Ubuntu distribution, aborting." Otherwise, it will install a big list of rpms etc to emulate the CentOS environment, and then the second command will build.