EDIT: Oh, and
Right now I'm trying to decide if it looks better with the FR/LG battle text box, or the default DarkViolet textbox. The reason why I'm considering using the default one is because the 4th gen games don't use a separate textbox for battles, so there's another thing that I might have to make consistent...
I'm also going to hack the HP boxes to look like the HG/SS ones. In Pokemon Jade, the HP boxes will look like the Platinum ones.
Originally I was just going to use the default Emerald battle backgrounds, but thanks to Frostbite posting new screenshots of his hack, I suddenly realized that it's possible for D/P/Pt/HG/SS backgrounds to actually look nice in a GBA hack, you just have to sort your colors carefully.
EDIT: Also, I'm going to raise Misty's levels a bit because some people say that she's kinda easy. Besides, it's really easy to train in this game thanks to the rematch system.