On the SVN changes, all I can suggest is looking for entries with "cache" in them. But no guarentee that will get all of them (there were a number of them as i recall, mostly made by Ashdigg).
On a related note, I was talking with savant yesterday, and he was just testing a datastore with pligg. Using a datastore should massively reduce query numbers for actions such as getting story data for the main page, as it will use 1 call to get all the data, rather than 1 + n stories calls. The downside is the 1 query will be a lot slower than the 9 quick calls (the saving on the front page with 8 stories was only 56ms) - however when the database gets busy, only having to call the database once will obviously be a big performance boost. I don't think this change will appear particularly soon, but it will be a good one!
One area we noticed a lot of queries were being generated on were comments. For example take a look at these 2 links:
http://news.oioplus.com/marketing/oi...ls-up-running/ - O comments, 14 queries
http://news.oioplus.com/politics/oio...ing-pligg-cms/ - 3 comments, 46 queries
Just wanted to give a heads up on that one, as with a lot of comments will rack up the queries very quickly. Looks like that will need optimisation, or caching, or both.