[Trac] working estimation into tickets

[Josh Stewart]

Hi everyone,
Im thinking about the best way to add custom fields and enhanced reports 
that will allow my team to track actual time against estimated time to 
complete a ticket.

Letting the developer add an estimate in a text box or drop down (with 
finite number of days est. to complete a task, say from 1..7), is fairly 
straight forward.
However I am not sure if its possible to add an addition field that 
needs to be entered before closing the ticket (Actual time to complete 
task).

Or perhaps there is another way? can the user set a expected date of 
completion on tickets? (like they can on milestones)....
And in the reports, could the query determine the delta between 
estimated closing date and closing date?

Has anyone got any thoughts on this or ideas for achieving some kind of 
estimation in reports against each ticket?

Josh