Engadget has an okay spec sheet here for all the phones announced today. No specs in the chart regarding battery life or capacity.

http://www.engadget.com/2010/10/11/windows-phone-7-handsets-the-tale-of-the-tape/

Of note, the Samsung Focus does indicate it has a MicroSD slot on it, so it seems external expansion is possible. Odd that it's the only phone to offer it, and still caps out at 16GB.