I was looking for a small project to get ramped up on Knockout JS. I ended up with this UI mod, which adds a small panel at the lower right of the UI (above the Chronocam icon) to display the set of units you presently have selected. It's currently limited to just displaying one build icon for each type of unit selected. At the very least, it's a good way to make sure you didn't just accidentally select a couple fabbers along with your fleet of fifty tanks. This modification includes changes to live_game_alpha.html and live_game_alpha.js, so I expect it will be deprecated in the near future. Also, this is not compatible with other mods that touch these files (i.e. all other UI mods), although I could post a diff if anyone wants to roll this change in with another UI mod. A few quick screenshots:
