The Reports module does support passing the PortalID, TabID, ModuleID and UserID to the query by using the following SQL Parameters: @PortalID, @TabID, @ModuleID, @UserID. So if any of those four parameters are used in the Query, they will automatically be replaced with the current Portal, Tab, Module, or User ID (respectively). This is done in a secure way, to avoid SQL Injection attacks. For example, if you want to retrieve information about the current user, you can use this query:
SELECT * FROM dnn_Users WHERE UserID = @UserID
Note that you must disable caching, otherwise one User may be able to see another User's results.
There are plans for a more detailed parameter system in future releases, but I can say this: Reports Module will never support TokenReplace due to security issues. TokenReplace is a very useful system, but the parameter system provided by SQL Server is much more secure and avoids SQL Injection attacks.