Never configured Apache that way, that sounds really interesting. I was running the site on a fairly well tuned LEMP stack and was using a cache plugin (forgot the name) but it would still choke fairly often.

Since the content of my site only changes a couple times a month I started migrating away from towards a static solution. I'm not trying to say WP is bad but I think if your content is relatively static and you aren't doing a ton of updating, just make it static HTML instead of doing hacky cache stuff. It's simple, secure and runs on any type of server.

The only thing that's lacking right now is a really solid static site generator. Octopress/Jekyll are good solutions but can be a bit frustrating and not very portable.