Timwi-
I assume you're currently file-caching complete
rendered not-logged-in
pages, right? Well, I don't understand why you have to do that, because
you're artificially limiting yourself to caching only non-logged-in page
views that way.
There's a lot of dynamic stuff depending on user prefs, from numbered
headings to inline javascript to TOCs etc. You would effectively have to
move much of the parsing to a post-rendering stage, which would be a major
PITA to code and complicate the already ugly parser beyond recognition.
About the same could be gained with much less work by caching DB-intensive
operations, such as link checking, using memcached. There's no reason why
we shouldn't have an index of all page titles in memory.
Regards,
Erik