I've worked on GameEX themes for years for the HTPCs I build. I have a few I'm not ashamed of to share at this point.
The themes are pretty generalized, so if you have custom setups per emulator/etc it may not be ideal for you. They have "avi" (Really h.264 encoded MP4s) and static png backgrounds for everything so can be ran animated or not.
I typically have a big gray bar across the bottom with a legend of what I've mapped my gamepads to but that seemed redundant for distributing them: This leaves a bit of space at the bottom that I should probably utilize better. It's designed for 1920x1080 but scales down to 1280x720 rather well. I'm assuming any higher 16:9 ratio resolution would also be fine?
There are a bunch of high quality logos for most console and handheld systems as well as some generic icons I built for the theme (Like the gamepad one shown in the example screenshots). There may be some older, lower quality ones lurking in there as well that can be deleted/ignored.
Attached are the themes. Through the magic of solid compression they decompress much larger (Dark Earth is 195MB and Organic Blue is 293MB)
2137282330_DarkEarth.7z 679228794_OrganicBlue.7z