Enhancement Request: Changing standard calendar to a company's fiscal calendar

We would like to have an option that allows us to select or even switch between standard calendars and our internal corporate calendar. For our company the first full week of February is our fiscal week one, then we obviously count through the year until we get to the end of the next January which is fiscal week 52. Depending upon how the dates fall there are times when we have a fiscal week 53. We would like the ability to manage by fiscal week.