@Aidaknow, @TungstenMD - I've created a tool (still beta version), that automates workaround mentioned above. It triggers whenever Windows background changes, takes a snippet of current background, and saves it to a file (you'll setup Aida64 to use this file as panel background and It'll automatically reload it's background whenever said file changes).
There's a lot to be improved, but it works as-is for me in Windows 8.1
I plan on preparing some more detailed description, and improving this tool, but since it might be hard for me to find some time - I hope this will somewhat solve the problem.
Note 1: Your input file will vary (it's most likely C:\Users\ [YOURUSERNAME] \AppData\Local\Microsoft\Windows\Themes\TranscodedWallpaper).
Note 2: Right now all wallpapers in slideshow need to be correct size, as no rescaling is implemented.
Note 3: If you've got problem setting it up please let me know. If it works let me know as well
EDIT: Second version is available to download at this page