Trailing slash after index.cfm file functionality

If you want IIS to send a 404 for any CF SEO URL like that then try adding a new handler to your web.config:

<system.webServer>
 <handlers>
  <remove name="Handle-CF-SEO-URLs-As-404" /><!-- for safety -->
  <add name="Handle-CF-SEO-URLs-As-404" path="*.cfm/*" verb="*" modules="StaticFileModule" resourceType="File" />
  ...
 </handlers>
</system.webServer>

This obviously needs to precede your .cfm/.cfc handlers.