OK, so I can upload both files here and you can use them at your own discretion, or put the code changes here (which would be a little messy...). I prefer the first option, but it's up to you. Of course, if you use my enemyunitpanel lua and xml, you should make a backup of your originals just in case... (uploading a mod for small changes does not make sense).
So, which do you prefer?
EDIT: @builer, from what I understand from the code (and tested when I made the bars higher), the window is made to resize itself when it needs more room for modifiers. The problem was that they "anchored" the window at a "too low" point in the screen, so the bottom was always overlapped by the opposing units windows. Re-anchoring the window by changing the offset did the trick, and as far as I understand, it will resize itself when needed, but will always be anchored with the bottom at that point (basically growing up, which it did as soon as I made the HP bars 100 pix instead of 85).