I agree, the answer to this question is not clear. If you are asking whether or not you could display some existing data field inside your app, the answer is most definitely a no.
But if you just want to write an app that looks and feels like the built-in apps and allows users to pick from a set of data fields (that are just bits of code written into the app itself), then yes. I've posted sample code in the past that showed a sample app with a single data page with 1, 2, 3, or 4 data fields that were user-selectable, so I know it can be done.
