Same issue here. Getting blank pages randomly. Like @skrause suggested here, clearing cache temporarily fixes the issue. Thanks to this post, I was able to trigger a blank page when trailing slash is missing.
Moreover, I'm randomly getting "bad cached pages", where the header area of the served cached page is messed up (the full page content is there in this scenario). Similar to the blank page issue, to fix I clear the page cache. What's puzzling is that for this one I have no explanation or a way to repro. No idea what's causing it or if it's related to the blank page issue at all.
Just curious, what environments is your Wordpress running on, mind sharing some details?
My site is running in Windows Azure, IIS, mysql, WP 3.5.1, in a multi-server env (distributed to two servers to be exact). Right now the W3TC plugin is creating cache in two locations. I wonder if this could be related to the issues I'm experiencing.