Apparently, this is a wide-spread problem. I received the following from Marware on 7/30/10, RE why they haven't fielded their cases for the iPhone 4:
"Hello Vince,
Fulfillment of orders for the following iPhone 4 cases has been delayed.
SportShell Convertible
Custom Shell
CEO Flip-Vue
Accent
MicroShell
SportGrip
Uni-Vue
The reason for this delay is due to a manufacturing issue that is related to the flash camera on the back of the iPhone. When a flash photo is taken the light bounces back and reflects off the edge of the holes in these cases and creates a distortion or ghosting in the photos. This problem only occurs in dark settings when the Flash is used, but it's a noticeable problem so the molds had to be taken offline to correct this problem. Apparently this is happening to many other case manufacturers. We are working to correct the problem as soon as possible, but this will increase the amount of time before we receive our inventory of these very popular cases by approximately 10 days.
We are very sorry for the inconvenience but feel the delay is worth the wait since it is our desire to deliver a quality product to our customers."
Vince.