So while I don't think I have the ability to mod a UI myself, I was just thinking.
Since there is now no hardcoded unit limit, and it has been observed that unit cards in excess of 20 "leak" from the panel, would it be possible to create a UI with smaller unit cards, allowing for say, 40 units? Make the unit cards half height, and maybe replace them with symbols instead of pictures. You know, like the little box shapes you get in turnbased wargames, the ones with the hexagonal boards. If anyone has ever watched a doco about a battleplan or seen a battlemap in a modern book, they should know roughly what I'm talking about. A more specific version of that.
Although now that I think about it, until there is some way other than scripting to get more units into battles, I guess it doesn't matter that much anyway.