After gathering dust for a few months in some deep and dark corner of my hard disk, my vCard-based Extended Presence plugin for Openfire is now publicly available here.
What this plugin does is add avatar (XEP-0153) and nickname (XEP-0172) information from your vCard to all your outgoing presence packets. This allows clients that do not support setting of vCard-based avatars (e.g. Psi) to still broadcast this information to contacts, such that clients supporting this avatar protocol (basically almost all clients, including the upcoming Psi 0.11) can still see your avatar. This server-side approach is basically what Google Talk does as well. For nickname support, this adds nickname information to presence subscription requests, such that clients supporting the protocol can present the request in a nicer way.
To use this plugin, simply put it in the plugins/ dir of your Openfire installation. It should then be listed in the Plugins pane of the admin console. You can then change the settings of the plugin (enable/disable avatars/nicknames) from the first panel in the admin console.