On the lookout for an iPad 2 case that integrates a keyboard but doesn't block the camera
Unfortunately, I don't know that a case meeting all of your criteria exists. It might be time to dig out the dremel tool and DIY.

My iPad keyboard solution is to use an inCase Origami Workstation and the Apple Bluetooth Keyboard. I don't carry the keyboard most of the time, but it does go into my bag if I think I'm going to be in a fixed location and do extended writing and when I  travel—where it generally stays in my hotel room for use at the desk. This doesn't meet your strict criteria, but it may be an acceptable compromise.