SSRS Web Services
The other day I was talking to another local developer that was interested in using reporting services, but while the “Report Viewer” control provided by Microsoft is fast and easy it doesn’t necessarily fit into the business requirements that his users have outlined. To that end it is a good thing that Microsoft provided Web Service access to all of the report servers functionality. Since a high level of customization is needed to the UI and the Report Server already provides much if not all of the data you need to build it my recommendation is to build the UI dynamically by queering the report server for information.
I would start by reviewing this article by Marian Dumitrascu. While his implementation is using RS 2000 and looks like the report viewer it should spark the seed to show you what is possible. SQL Reporting Services Viewer Page Using SOAP API (http://www.codeproject.com/sqlrs/SQLRSViewer.asp)
Some general information about the Report Server Web Service can be found here: SQL Server 2005 Books Online - Building Applications Using the Web Service and the .NET Framework (http://msdn2.microsoft.com/en-us/library/ms154699.aspx)
Finally if you want to render the report and return it to the user as a file take a look at this article: How to create a sample application that uses the Reporting Services SOAP APIs to render a report to a selected file format on a Web page (http://support.microsoft.com/kb/875447)