You could start with an intermediate stage, with say a query-builder wizard that walks them through the process. 1. What type of report would you like to creat

You could start with an intermediate stage, with say a query-builder wizard that walks them through the process. 1. What type of report would you like to create? (define the domain) 2. What are you looking for? (define the topic) 3. What limits are there? (define the data boundaries) 4. How do you want it displayed? (report output format like excel, pdf, etc). See how a select group of customers like it and get feedback on it ... some might immediately say "yes we want something more powerful" or what you have will be just fine. From there you can decide if you want to pursue exposing the query-builder more openly than a guided wizard, and if you want to charge extra for it.