I managed to find an Unborn Valkyr! Woohoo!
What an amazing looking pet, was so excited to try and get one of these as soon as I could and I lucked out when flying through Storm Peaks! I found her at the co-ords 29,50 where my marker is on the map below:
Unfortunately the quality of the pet was poor, but nothing that a pet stone can't fix! Really just so happy to have one, another to check off the list. The spawn conditions are still unknown for this pet, I'm very very intrigued to hear later down the line what they thought of which was so unique with this pet!
Only time will tell ;)