You might be able to write a macro in VBA that sets a text field to equal the value in a particular field for a different task.

For example, I think you can work with the Tasks collection object (basically the list of all your tasks) to return a field property for a particular Task object and then assign that property to the text field of another Task object.

I'm rusty with my VBA or I'd try to write a quick macro up for you... If I find time, I'll try to write one and respond if no one else has.