Wanted: Ultra lightweight CMS

Dear Lazyweb.

We are looking to replace Drupal with something more lightweight. The virtual server we host boblycat.org on is pretty cramped for space, so the price of a couple of apache instances running Drupal, plus MySQL sitting in the background, along with the rest of our services, is sometimes too much for the available RAM. The result: some not-so-surpising OOMs, and a script which prophylactically restarts Apache every now and again.

What I'm looking for is a solution that combines a gallery with a wiki with a blog. It must be multi-user, and each user must be able to have his own theme. LDAP integration would be nice for auth. These could be three different pieces of software, but proper gallery and blogging integration is a must for our current clientelle, which lives under the delusion that photoblogging is fun;P For the rest, integration between the wiki and blog is desirable.

If anybody knows of any gems hiding out there that fits this task, don't hesitate to get in touch.