nUrlRewriter Version 2.0.0.4 provides for a wildcard topLevelExtension extension of "*" which in turn indicates to nUrlRewriter that all web page extensions (including the absense of a web page extension) are to be considered candidates for nUrlRewriter processing.
Download file contents are described as follows...
nUrlRewriter2004.zip - Contains full C# source code VS.NET 2008 project, test web site project and documentation in .chm help file format.