Create reports view on magento

for our shop i need to create custom reports view. here is the story in big: Clients can have their own shop in magento (they have their own store view - limiting their permission will be done by the advanced permission module to upload / modify products and see reports only) the report will collect data from 2 sources: 1. store sales logs (the usual magento report) 2. predefined parameters that admin will define for each client / store then the newly created report will then collect both data and make calculations as per defined in the excel sheet. please note, users will be able to see the admin predefined parameters, and cant change them, while admin will be able to modify. - the reports view will contain 2 kind of view, sortable (just like in magento reports, user can define the dates he want to see the reports) - monthly statement view (this will be fixed view and look like an invoice)