I have spent a large amount of time trying to determine the WSoD issue with OpenPublic. Continuing research shows that it is a server side issue and is not specific to a particular browser, as I originally thought. All my server memory and php settings are even more generous than the settings recommended on the openpublicapp.com site.
Even more frustrating, Apache is not throwing any errors, other than the "lost favicon" error that happens to most Drupal7 installs. What makes it particularly maddening is the seemingly random nature of the error. Time seems to be a factor. When one gets the WSoD, you can refresh the page and everything will begin to work. This "refresh" also seems to help other browsers display the site correctly, as if a cache is being refreshed. In fact, flushing all caches is another way to "get things working" for awhile.
But as time goes by, the site breaks yet again, usually after 10-15 minutes or so. To my knowledge, my server is properly set up, and I DO NOT have this issue with any other Drupal or Drupal 7 install, so it is specific to OpenPublic.
This is a SHAME because I was planning to use the excellent OpenPublic profile as the base for a commercial site to launch in a few weeks, but it looks like I'll have to abandon that if I cannot resolve this issue soon.
Any help or hints would be greatly appreciated!