Justin - the calendar listing is still dependent on race directors going to the USATF site and listing the event. I found 4 5k events in Colorado in July, and there are at least 20 5k events that use certified courses.
I realize any listing is only as good as the information entered into it, so any voluntary-submission calendar is incomplete. That is why I am suggesting the race Website be on the cert - so runners can look for races of a particular length in their area, from the entire list of certified courses. A better chance of getting good information.