Try this one: https://slashie.net/cvrl/slash-barrett_800x600_64x64.ui
Just place it in the directory and then run `java -jar cvrl.jar sgfx slash-barrett_800x600_64x64.ui`
It may look a bit cramped; I tried setting up one with smaller icons however the engine is currently hardcoded to a 64x64 grid size; might change that in a future version.