Strategy for creating a CalendarDatePicker with keyboard entry

[amtopel]

Although there's a proposal for it, it looks unlikely that the CalendarDatePicker will ever support keyboard entry. So I was looking for advice on how to go about creating my own. My goal was to create one that resembles the Win32 Date and Time Picker, with the calendar flyout.

First, do you think this is a job better suited for a ControlTemplate or UserControl? And do you have any strategies you'd use for assembling the control, formatting and validating the date numbers, etc.?

Any guidance is greatly appreciated.