You mentioned you were unable to find the updated (2008) Liberation font family with a slashed zero. I found a version with a dotted zero tonight via a Google search for "Liberation Mono" which yielded a first item entitled "Liberation fonts" (http://en.wikipedia.org/wiki/Liberation_fonts). This appears to be the Wikipedia page you mentioned above in the body of your article, as it has the quote re "The fonts were developed by Steve Matteson of Ascender Corp....licensed by Red Hat, Inc. as the Liberation font family."
The current version of that Wikipedia page states "The Fedora Project, as of version 9, features slightly revised versions of the Liberation fonts contributed by Ascender. These include a slashed zero and various changes made for the benefit of internationalization." At the bottom of the page there is a link to the "Liberation Fonts project at Fedora Hosted" (https://fedorahosted.org/liberation-fonts/).
In the zip file you link to, the bold, bold italic, and italic mono fonts are version 1.04, and have a dotted zero. However, the regular Liberation mono font (LiberationMono-Regular.ttf) is version 1.00, and is not dotted.