Hi there, friendly neighborhood web developer here with my $0.02. Forgive me if I'm saying something that is already known, but given that 1. this problem is happening across multiple platforms and browsers and 2. never, ever ever happens for me and 3. it's a -BLANK- as in white (right?) screen, that tells me it's most likely a server-side problem as opposed to an end-user problem. Furthermore, as a Drupal developer I'm very familiar with ye olde WSOD (white screen of death). Given that this forum has grown by leaps and bounds over the past year, and given that a lot of people are starting to go on vacation and have more time to post/loiter on the forum, this leads me to believe this is most likely a memory or other resource problem. In my mind that's one of the few explanations for intermittent failures.
Denny etc, I'd be happy to try to diagnose the problem if you can't get ahold of your admin types.