Branding/homepage:

make a collage of the user photos in the shape of libravatar logo (the ones licensed under Creative Commons)
improve basic layout (using http://960.gs/ maybe? or perhaps a responsive design framework?)

Federation

create a test mugshots.debian.net server with db.people.org auth as suggested by Lars)

Gearman jobs

make gearman jobs persist (inside a Redis DB?) but not inside the main Pg DB

Sysadmin stuff

create a staging server to test deployments
create a public package repository to upload libravatar packages
use rsyslog to copy logs to another machine (useful in the case of a server compromise)
use Puppet or Salt for all server config
monitor server with Nagios
monitor gearman queues (http://labs.consol.de/nagios/mod-gearman/)
use mod_spdy for all HTTPS serving