Vagrant Shell provisioning to replace default chef install with omnibus installer. Tested on the default precise64 boxes provided for Vagrant.

Vagrantfile

Vagrant::Config.run("2") do |config|
  # Clean up the default image to remove some default puppet, chef, and ruby.
  config.vm.provision :shell do |shell|
    shell.inline = <<-EOF.gsub(/^ +/, "")
      # Make sure vagrant always has sudo access
      ( cat << 'EOP'
        Defaults exempt_group=vagrant
        %vagrant ALL=NOPASSWD:ALL
      EOP
      ) > /etc/sudoers.d/vagrant
      chmod 0440 /etc/sudoers.d/vagrant

      # Remove vagrant path changes (not using the default install)
      if [ -f /etc/profile.d/vagrantruby.sh ]; then
        rm /etc/profile.d/vagrantruby.sh
      fi

      # Remove vagrant default executables (again, not using them)
      if [ -d /opt/ruby ]; then
        rm -rf /opt/ruby
      fi

      # Install chef omnibus package
      if [ ! -d /opt/chef ]; then
        wget -q -O- https://www.opscode.com/chef/install.sh | bash
      fi
    EOF
  end
end