Shortest lived iMacs ever...
I can't imagine Apple refreshing the iMac line after only two months, no matter how convincing the update. The only other times Apple does that are silent updates; for example, the iMac rev. B, released shortly after the first iMac, was very silent and secretive, and Apple deliberately tried to hide it. It was also really minor, just a change in the graphics card, not something major like a new monitor.
But still, rumors of an LCD iMac remain. This reminds me of the rumors of a 17" iMac shortly after the original iMac. A few months later, Apple announced a 17" monitor that had the iMac's bulbous design. My guess is that this "LCD iMac" isn't an iMac, but something totally different, possibly some kind of LCD all-in-one Mac, in the spirit of the late Cube. Or, it could be an iBook dock with an LCD monitor on the front. It could be a hydrogen fuel cell, to replace the TiBook battery. Maybe it's a mirror with voice recognition. Perhaps a portable Playstaion 2. With Airport. Whatever. It's not an iMac. But it probably does require Mac OS 10.1, which is why it wasn't announced at MWNY.
As for TiBooks: definately be updated in Sept, maybe even at Seybold, but definately by Paris. I was looking at getting a TiBook for school this year, but decided instead on a Quicksilver G4, becuase it was so much more convincing than the TiBook. I'm guessing the major changes will be a combo drive, NVIDIA2GO, and a speedbump. I'd love to see a Superdrive, at least in the high end, multiprocessing, at least as an option, and colors, although I'd personally stick with titanium.