I created this simple theme based on the sd card menu for USB Loader GX.
My only true modification is that I "removed the install and shutdown buttons on the main screen".
I always thought that, although I really like USBGX, the main screen have a lot of buttons and I made a simple trick to hide them, since the program itself doesnt allow to completely remove them. These buttons are redundant, when you insert a disc it already asks if you want to install or run the game. The shutdown button, aside pressing the power button on the wii remote or the console itself, you can show it on the home menu of the loader by going to the gui settings and enabling the full home menu and now, when you press the home button the options Exit and Shutdown will appear instead of the default Wii Menu and Homebrew Channel (which you can still do with the full menu, clicking exit will ask if you want to go to the wii menu or homebrew channel)
There are two folders inside, one for normal use and other for hdmi use, such as wii2hdmi and such.
Some devices like the wii2hdmi have a slight more amount of contrast applied to it, so instead of displaying as intended, a dark gray background like using component or composite, it shows like black instead, but you can use it if you want to.
There is my theme for Savegame Manager GX that is kinda like a companion piece for it: