Scheduling resources (internal & external) without a Project Plan

I am working with a client (outside construction with internal and external resources) who wants to create and maintain a scheduling workspace/tool.  Presently, they assign work in teams against various initiatives and urgent work orders. The goal is to ensure all resources are fully utilized and work is prioritized.  When a new initiative comes into the  department, the schedulers need to assign available resources and if necessary, reassign resources when the need arises.  In addition, the solution should help engineering and design when creating a timeline for the various intitiatives.  In otherwords, a pipeline view of existing and future initiatives.  

I am looking for ideas and suggestions for structuring a solution.  Any information and/or suggestions are greatly appreciated.  

Thank you,