Question Create a custom dropdown with custom items

I'm attempting to create something like this with UI Toolkit

I'd like to create a component like the DropdownField, inherit from PopupField, and setup custom children that will accept something like a list of hex color codes in the choices field and render something like the above. On click it would return the hex color code that was selected.

I'm struggling to find how to use uxmlChildElementsDescription and setup traits that would do this, can anyone provide an example or possible solutions?

(I'm assuming there's someway to set the background color of each child's style inline from the value that's passed in)

 

And here I am just trying to add some styling to the foldout of the builtin DropdownField, but that seems impossible