This is what i did... I have a case i bought from verizon the soft plastic one and i used scissors to cut around the platue part. it stays on my phone great and it still protects the front and all corners. I have enclosed pics.
Depends.. Are you looking in stores or online? Tons of websites like Amazon have them. And I saw an extended battery for the Incredible 2 at Best Buy before.
I bought this one and it serves it's purpose well. It's just the stock Verizon TPU case with the back cut out but it fits well.... My only real beef was that I bought the "black" case and it's actually clear. That being said it still looks black once it's on the phone. Cases for the Dinc 2 with extended battery are far and few between...