Can you give advice on how to/can we sponsor relative date/time selection?

This is for the same reporting system as the time in the previous
enhancement suggestion.  We want to give users the ability to set up a
custom report and then arrange for delivery.  Part of the customization is
date/time selection.  When doing recurring delivery (I want this report
sent every day at 8am), a standard date/time picker is not relevant without
a great deal of UI and intelligence to advance dates the right way.  

It's cleaner and simpler to give them the ability to pick "last week" or
"last X days" instead.

Cheers,
Ernest