It is possible to PXE boot a full blown OS, not just OS installer, Live CD or CoreOS.

The product usually used to do this is: http://support.citrix.com/proddocs/topic/technologies/pvs-pr... It is just a nice GUI that ties into PXE and TFTP and just streams an image from a disk file.

On a 1Gb network I have booted over 300 physical machines in under 2 minutes simultaneously.

For those curious, unfortunately PVS is packaged with XenDesktop so you have to buy XenDesktop to get PVS. Citrix does not seem willing to separate the two as different products even though I have deployed PVS for several customers without even download the XenDestkop bits.