The only thing I can find even remotely similar to what you are looking for is Snapture."Snapture had brought quite a few features of a digital camera that were missing in iPhone's camera app such as 3x digital zoom, delay timer, toggle auto rotation, burst mode, color modes, leveler etc.Snapture 2.0 is available in two versions: Snapture Basic which is free but ad supported and Snapture Premium which is ad free and includes the QuickView feature costs $7.99. "The delay timer might do the trick of what you are wanting, but not completely. Sneaking photos of people and things is made difficult for a reason, I would assume...! Some places might accuse you of spying or of trying to photograph their products or designs, if they knew you were doing this.But give 'em a little time, and someone will come up with what you are looking for, I'm sure.
iPhone