What is the range of values of X? Your desired daily email digest has just the actions due that day, or what?
A refurbished 16 GB iPad with a copy of OmniFocus for iPad gives you a nice forecast view for values of X up to 7, plus access to your tasks in a mobile format. Pick up a copy of my buddy MacSparky's
iPad at Work book and you'll probably find many more uses for it. Omni is working on bringing the forecast view to the Mac application, but it's difficult to make plans based on when they'll deliver unless the item in question is already in beta test, and it isn't.