The scope of an SAP implementation can be so extensive... What tools are available to help describe the future "Application Architecture" in terms of what SAP modules or bolt-ons support what business processes? I have seen the SAP Solution Maps... Is this a tool you would recommend to describe the future state in terms of application coverage?
The SAP solution Maps are a good place to start to begin to describe your future Application Architecture. It is a useful communication tool to be able to document what business processes will be incorporated in specific SAP modules and bolt-ons. If the complexity of your business has taken you beyond using a simple drawing tool like Visio, you may want to investigate more sophisticated modeling tools. Such as ARIS by IDS Scheer or Catalyze by SteelTrace.