here is some one that pxe booted the pi or some thing like pxe
https://blog.mythic-beasts.com/2016/08/05/sneak-preview-from-mythic-labs-raspberry-pi-netboot/

Darn forgot to add a link
https://www.raspberrypi.org/blog/pi-3-booting-part-ii-ethernet-all-the-awesome/

Hello Just a heads up Raspberry pi 3 is working on pxe support

https://www.raspberrypi.org/documentation/hardware/raspberrypi/bootmodes/net.md