The U115 will not come with a 3-cell battery, it will come with a 6-cell battery. I get almost 3 hours out of my U100 with a 3-cell, so it stands to reason that you could get 6 hours from a 6-cell without any design changes. Add in the fact that it will be using the lower-power Atom Z530 (as opposed to the Atom N270), along with it's MUCH MUCH MUCH lower powered chipset (as opposed to the standard Intel 945 originally design for desktops), and you'll see even more battery life. And don't forget that they'll be using an SSD instead of a mechanical hard disk.

All that being said, I think they could hit 10 hours without much trouble. Just imagine one of these with one of the 3rd-party 9-cell batteries...

I believe this is the first Atom system to use Poulsbo. This replaces the crappy 945+ICH7. That means a 25w+ chipset combo is now down to a single 2.3w single chipset. MSI will also be using the Atom Z530 instead of the standard Atom 230. This saves another 2w. Saving 25w with better components really helps battery life more so than some SSD/HD hybrid (which should save less than 5w).