Nice article and something I've done numerous times, though in past ive used it for seasons, especially usefull in the retail and the travel industries, where there are Spring/Summer, and Autumn/Winter derivations.

The only thing I would suggest is that you set the Name column attribute on the ID hierarchy to to Calendar Date and change the name from Id to be Calendar date. This then makes the Calendar Date attribute hierarchy the key member, it also avoids confusion for the end user who will understand what a calendar date is but not an ID.