The Project Management console has a team tab which is pretty good in general to add people to the team, where it's missing functionality is to have additional fields to track the stakeholder registration. Aside from the role, the additional stakeholder fields are:
* Influence/Power level - their ability to cast decisions on the project
* Interest Level - their value to the project
* Support level - their ability to support activities
* RACI concepts of Responsible level, Informed Level etc.

* Function - what they are actually doing
* Expectation - what their focus is
* Communication Requirements - how to best reach them

Those are just some samples in stakeholder registration so if clients can define this as UDFs that just may be enough.