Task Item Due Date - Not just Start and End Date

Task Item Due Date - Not just Start and End Date

Is it possible to have Task Due dates, instead of just a Start and End date? I see that it is valuable to track the actual start, end dates ... but for dependencies, and when a project is initially started may only need/know the 'due' date... not how long it will take.

For example, on my project I have some client task requirements - I don't know when they will start... but I do know when I need to have them completed by for other dependencies.
Coby Pachmayr