I think the Protozilla package may do what you're looking for, although I haven't tested it.
Protozilla Examples says
A protocol handler with the extension .url is treated as an "URL re-direction" specifier, rather than an executable program. For example, a handler named moz.url may contain an URL prefix, such as http://mozilla.org/. In this case, the URI moz:docs is translated to http://mozilla.org/docs. The peer-to-peer freenet protocol uses a local proxy server accessible on port 8081. To be able to use freenet: URLs in the browser, all you need to do is to create a file named freenet.url containing the text http://localhost:8081/. (Of course, you need to be running the freenet proxy server as well.)
heck, it might be possible to tie this into tye's usage of a cached supersearch page as well, something like pmsupersearch://auth=boo_radley;title=foo;startdate=bar;enddate=baz