If there is one thing we can say about Windows Phone 8 is that it is reportedly very secure, specifically during the boot process. But that doesn't mean that the OS cannot be "dumped" and looked at for exploits or--the holy grail--to be back ported to older Windows Phone 7.x handsets.
That process has now officially begun over at XDA Forums where a user named 'neilgoco' has managed to get his hands on an HTC 8X engineering device. That means it is more 'open" and has access to developer tools not found on the commercial release.
The dump so far is 14GB and due to his slow internet connection cannot be directly shared, though he is looking to share it physically via a 32GB flash drive for others. He's also been able to glimpse at what appears to be the OS partition (2.29GB, sounds accurate) and a few other "hidden" ones as well.
This work is of course all very preliminary i.e. it's like discovering the cave but the real hard work is yet to come. We wouldn't expect any usable results for a few weeks at minimum but more likely a few months. Still, for those in the community this is always a lot of fun.
Source: XDA Forums; Thanks, mcmaui, for the link!