You can see an example of what stakeholder maps look like here.
Since 1994, and in addition to worrying about relationship management in general, Dr Jon White and I have been puzzling this question and for a number of years we have been using a technique called 'visualisation' (there a quick primer about Visualisation at Wikipedia including Knowledge Visualisation, and Information Visualisation ).
Visualisation allows groups of people to develop visual representations of the relative significance of different stakeholders. The latest version of software to aid this process was developed by Renderspace, part of the Pristop PR group, is called 'Publigram'.
An example of Publigram in action gives you an idea of this kind of Stakeholder Map.
The icons, in this instance, showing the relative importance, influence and attitude of stakeholders as described by a stakeholder group. The use of stakeholder groups is, in this instance effective because of the use of visualisation and draws on both explicit and tacit group knowledge.
Stakeholder maps have been in use for years. They can be developed using a whiteboard and sticky labels. One of the advantages of using software is that all the features of the whiteboard approach can be incorporated and, in addition, we can use the visual model to provide statistical representation of decisions made by the focus groups (see below). With a statistical view of the present and future ambitions of the organisation, one can use gap analysis to identify where most change is required among stakeholders which offers and aid to planning and (later) evaluation.
An example of the statistical output from the Publigram software is shown here:
There is more information on our Wikis http://theclarityconcept.pbwiki.com and http://publigram.pbwiki.com