Case management functionality - ideas

twowheeler posted some suggestions on the forum:
Part of our organization does mentoring of troubled young people.  We train the adult mentors, match them with a "protege" (the young person) and track the progress of the relationship over a period of time.
Already in CiviCRM I have built in custom data fields representing if the contact is a mentor or a protege, when the mentor started training, when they finished training, when they were matched to a protege, etc.  Also there is a CiviCRM relationship between the mentor and protege contacts. 
I think what we need as a next step are work queues, a canned search on certain items that presents a report to the user which says, here are the people who signed up to be mentors who should be invited to the next training, or here are the mentors who need a phone call to check on progress.  It would be nice if a work queue could be assignable to a particular user or group of users, but not essential.  I suppose that a work queue could be as simple as a custom report.
There would need to be a way to define the steps in a process so that once a contact is marked as completing one step, they move to the queue for the next step.  The steps could be defined to be most anything, like starting with an indication of interest on the web site, to attendance at an event or a phone contact or receipt of a form with a signature.   It would be nice if a time period could be associated with a step in the process, like step 3 should occur within 60 days after step 2.  The staff's job would be to keep people moving through the queues.
My other concern is how we keep a history of such actions.  At the moment I only have one set of custom fields in the contact for this data.  This is not ideal.  If a mentor continues with us and is assigned a new protege, we would end up overwriting the first data set with the new one, so the history would be lost.  So perhaps we need a new concept of a case that would be filled with whatever custom data is needed.  One of the fields would be an arbitrary case number or code.  Mentors and proteges would be associated with one case, and then the case would be moved through the work queues until it is closed.  Each contact could then be associated with an arbitrary number of cases, similar to how you currently handle events.