Hello! I'm not quite sure what you mean, but am interested in the idea and would like to know more. When you say "time tracker field", do you mean a literal field, or space, in which Tasks lie to be counted up or tracked for time?
EDIT: Or do you mean a field in the Task that one can use to enter how long a Task should take to complete?
And I do want to add something for time / day estimations for Task completion.