Expense PO for Drop ship Inventory Sales Orders

Is there a way to create expense POs for drop ship sales orders with inventory items. We are using projects to capture project/task/expenditure type at drop ship SO. 

We want expense POs since Projects works currently without any issues for expense related POs and reflect in project status inquiry and other Project related solution. There was a suggestion by Oracle to set up Project manufacturing but that model does not suit our requirements and causes changes to current custom processes. We are thinking to override the requisition interface to make the req - expense and update the project/task etc before req import. Any major concerns/impacts with this approach or is there a better solution without dev effort?