it is currently possible to create a CLM Option for choosing the Virtual Guest Package. This is only usable for template-based provisioning, but not for baremetal provisioning (PXE-Provisioning).
Jeff Turner created an article about choosing the template via option in February 2015:
Our problem is now, that we cannot specify the Operating System as an option (as we are using baremetal provisioning). Therefore it would be great to have the same option as in the blueprint - where we can specify wether it is templated-based provisioning or baremetal provisioning - to specify also an operating system to be installed.
An enhancement of this idea would be to also select the option wether it is a physical machine or a virtual machine.
It would be great if this option would be available in the next release of CLM.