Not to piggyback on beano311, but he's correct. Not only is it not possible to have a .VHD mounted as a USB drive over a cable coming out of the PC (I looked, could not find an application that would emulate a USB client over USB with a VHD to a USB host), but even if it were, it would unfortunately accomplish nothing new. People have already taken WiiU formatted drives, plugged them into their PC and taken dd images of them and poked around with a hex editor. Unfortunately it didn't provide much information -- the drive format Nintendo has used for the WiiU is encrypted (even seemingly at the MBR level). People who have intimate knowledge about the data on the drive itself were still unable to locate that data or any headers to it. Most everyone who has looked has come back saying that the data on the drive is encrypted and until that can be worked around, there isn't much to be found by poking around in the images.
Due to that, a disk image of the drive itself won't really help until there's a way to decrypt it. It doesn't really matter if it's a dd flatfile image or a .VHD. This could either be an exploit in the console to obtain the decryption keys (likely specific to the console, based on the fact that people who have returned their WiiUs for repair get them back and their disks don't work), or if we ever get homebrew running on the WiiU directly, it's possible that someone could call the function that decrypts the drive on the fly, and have it write-out the data to either another drive or another location on the drive in unencrypted form.
In any case, while this specific idea probably won't lead to any discoveries, don't be discouraged. Learn more about how everything works and use that knowledge -- everyone working on these kinds of exploits and homebrew were once someone with not much knowledge on the topic who had to learn about it in order to be effective.
I'd love to play Zelda or KH 3D )
