Wow.. Did you know there is a team at oracle called
"the Real-World Performance group" ?? Well either did I.. This group does exactly what you would expect.. They look at real world customers, and find ways to help things scale..
I came acrosss it while I was "chatting" with a member of the team, Greg Rahn.
Here is his blog.. http://structureddata.org/
I'm going to have to do some reading on performance ideas.. I read one of his articles on the optimizer, and he was dead on.. He also does presentations at Openworld on the topic, along with the unconference.