I was wondering if anyone is making/selling any custom design battery covers. It seems like a great idea and could really make the phone look great
Not to the best of my knowledge, but there are numerous websites that sell skins to put on your phone. They're similar to a sticker, and they're custom sized to each specific phone model. On a lot of the sites, you can even customize them by uploading a photo or image and having them make one out of that.
One of the things I whined about right after getting the Instinct was that a metal battery cover would be a little nicer than the plastic one, but... between the D-Lo Jam Jacket I started with and the cheapie $7 ebay hard snap-on case i currently use.. i haven't thought about it since. Food for thought, though, either as an official accessory or for the phone crap manufacturers to jump on.