The Overview Document for CLLARE is indeed very out of date, and there is nothing more recent, I'm afraid.
The basic situation is this: not too long after the latest version of the Overview Document was published, we all realised that the current way we were operating, with people just making decisions in the forums informally on instincts and rough calculations, was not going to work out well in the long run. We decided we needed a slightly more structured process, where we broke design tasks down into subtasks, and each subtask had to be voted on, etc. The main process involved in this is called the Engineering Process, you can read about it on the Wiki and all over the forums.
In theory, we are now working on fleshing out those processes so we can revise our old design and carry forward in a reliable, sustainable way, and it wouldn't make much sense to update the Overview Document until that process is in place.
In practice, very few people have actually contributed to the planning of the Engineering Process or the implementation of what has been planned so far, so design work has effectively come to a stand still. In fact, CSTART itself has effectively come to a stand still lately, with a lot of regulars absent for an extremely long time. This stagnation is frustrating and is largely what motivated my recent "kamikaze" post.
Assuming we recover from this and some proper processes get implemented, after that happens we should start to see progress on things like the Overview Document again.
I am working on a few documents currently, related to CLLARE design, which I will post drafts of soon. If work on the Project Management and Engineering Processes etc. ever take off, I will insist on something being incorporated into them to accommodate these documents.