Putting each message in its own table should minimize or localize the problem, and present more reading during page load of long threads, since tables on some browsers don't display until fully loaded.
Hmm... too bad there couldn't be some sort of user preferences to choose board presentation style, defaulting with a pretty tables one, but also having a more general non-tables option for those who consider practical function priority.
I think the long dotLRN Governance thread http://208.184.248.90/forums/message-view?message_id=45344 is another good example to test against any presentation style.
