I've tried creating my own version of a UIPickerView element for MonoTouch Dialog, but it was to no avail. Is there some form of it already implemented within MonoTouch.Dialog or a way I could edit a DateTimeElement to act as a UIPickerView with my custom entries?
Cheesebaron has done this - see the code and discussion in https://github.com/slodge/MvvmCross/pull/25
The base of this code is indeed based around the uipickerview inside the dateelement