add time estimate to ideas

I like the vote system to know how many people are interested by a feature, but another important factor to consider is time to implement.

I would love to see a time estimate field in the admin console (just for admin purposes, not shown to end users) so that we can defined expected number of hours, days, etc to complete the task.

Then, I would like to be able to sort ideas by :

1) Vote counts (like now)
2) Time estimate (asc or desc)
3) Votes / time estimate

#3 is the most interesting here because it would allow us to see the 'quick wins', i.e. what is the cheapest way (timewise) to please a user. Ideas with less vote count often get forgotten, but if our reports would show that we can please x number of people with insignificant deployment efforts, it may worth doing it.

Keep up the good work.