This scenario is not possible since as you have already noticed the parameters get duplicated. However you should know that a much more cleaner scenario would be to create a report that you are going to use it as a template and whenever you are creating a new report just use this one - there is no need to inherit from some base report.
the Telerik team
Have you tried the new visualization options in Telerik Reporting Q1 2013? You can get them from your account.