Milestone as Range of Dates

It would be very helpful to us to have the option of a milestone task as a range of dates.

Many of our projects include 2-3 days of training with a client. These are scheduled events we have to plan our projects around. It's confusing to our users to use a milestone since it only signifies one day. But when we use a regular task for this training item, the gantt chart can easily get messed up when adjustments are made because of dependencies related to the training task.

Thanks!