Some months ago, before the great restful reorganization patch (#1901), I created a small feature called project tinyurl.
This is a supersimple action that provides an unique permalink to a project path and redirects any request to the real project URL.

Example:

http://www.redmine.org/redmine => http://www.redmine.org/projects/show/redmine
http://www.redmine.org/foobar => http://www.redmine.org/projects/show/foobar

Here's a couple of real world examples:

http://code.simonecarletti.com/www-delicious
http://code.simonecarletti.com/apachelogregex

I forked Eric's repos on GitHub and provided a full patch along with functional and integration tests.

http://github.com/weppos/redmine

All changes are available in a separate branch called @tinuyrl@ (ehm... I mispelled it on creation!).