ical and to-do lists

I was just wondering why iCal doesn't have another bar on it: there's a bar on the left for our list of calendars (and a full month calendar at the bottom of that) and then you have the calendar that takes up the right side. Why can't we have a third bar that runs along the bottom of the calendar when we have it set to look at a week at a time? That third bar is divided up so that it aligns with the day above it. In those spaces we could create a to-do list for that day.

Just as we are able to assign a colour to a calendar for each facet for our lives (e.g. purple for work calendar, green for meetings, etc.), we would be able to assign a colour to each task so that we know if it is work-related task, phone calls to make, errands to run, steps leading up to the completing of a project, grocery list, etc. We could check them off when we complete them, but it wouldn't necessarily delete them. (I hold onto old, work-related to-do lists for a year because my work is cyclical and I like referring back to them for details or a timeline.)

And just like iCal, we would be able to set a starting and ending date and time, alarm, notes, invite, URL, etc.

Or maybe I'm just asking for too much and this would only be useful to me?