I would like to test it myself.
I will have some holidays soon, (maybe end of this month).
no promise, you all know I always end pushing the release to later...
yes, and no.
There is something like you want, but I'm not sure this is what you really want.
1) legal channel
if you only want a way to launch USBLoaderGX from WiiU, then it's available here :
https://gbatemp.net/threads/usb-loader-gx-forwarder-channel-for-wii-u-menu.482595/
Edit: I added that link to the first post, in the download section.
You need to install :
USBLoaderGX boot.dol on SD or USB (like always)
USBLoaderGX forwarder channel UNEO on vWii
USBLoaderGX forwarder channel on WiiU from the link I gave you.
This is a modification of hbl2hbc (WiiU homebrew loading vWii with system menu patched to launch vWii Homebrew channel), except here it's modified to launch UNEO instead of HBC.
When you exit a game, it will stay in vWii mode.
2) not legal to share channel
If you want a WiiU Wii virtual console injected with USBLoaderGX forwarder, then I can't provide it as that type of channel contains copyrighted files from nintendo (fw.img is actually IOS255)
If you want that type of channel, you need to build it yourself by using "WiiVC injector Script" program (you can find it in WiiU hacking section) and select the forwarder.dol located in "all-in-1 package/wad/forwarder".
install the resulted channel with WUP installer.
you don't need the vWii UNEO forwarder channel to launch USBLoaderGX.
This launch method can only be used to .... not so much yet.
You can't launch Wii games or emuNAND
You can't launch channels (haven't tried, but I'm sure it might not work)
Maybe you can launch nintendont ! (haven't tried either)