I actually read the topic on OTN, and it looks like you've looked into every possible problem apart from the cups themselves, could they have flared? The bearings are pretty solid sealed cartridges if I remember rightly, so I doubt they've shrunk. If you work in a bike shop, you should have a vernier, so you could try measuring the bearings and then the diameter of the cups to see if they have flared. It might also be an idea to measure the cups in line with the frame, and across it, so then you can see if the cup is oval.