I am building an iPhone app that will need to display info primarily in a calendar view. Users will need to be able to search for entries and view them by day, month or in a list view. It seems like the built-in calendar type interface is ideal for my app. So I could build a similar calendar with 3 buttons at the bottom for list/day/month view as well as a button for today, in short a very similar interface to the built in iPhone calendar with different colors primarily. However, if I replicate it am I a) a lame copycat for replicating the built-in interface or smart for using a well-known iPhone metaphor and b) in danger of having my app rejected?