Click To Install for the current SVN build of Navit is now available at http://tech.visser-scully.ca under the N8x0 downloads page.
the first time you use this a message from Application Manager comes up asking if ok to Navit SVN Builds to the Catalogue. Then Navit installs.

One of the blog posts there also give a php code snippet in case your ISP (like mine) does not support mod-mime and custom mime-types. I added the snippet to WordPress Download Manager's download.php file. This is required for .install files, otherwise they serve with Content-Type=text/plain in place of application/x-install-instructions.