Have you seen Steve Huffer's link the OEM W8 ISO file?
http://h30434.www3.hp.com/t5/Notebook-Hardware-e-g-Windows-8/Need-Product-key/m-p/2592907#M96681
This will be perfect to use for clean installs on HP PC's that came with W8 or if someone installs a smaller SSD and their recovery disks don't work.
I made a bootable DVD of the file but I have no W8 PC's to test to see the BIOS product key activate the install.
The file works and everything because I ran it.
Steve posted that the BIOS key does work though.