If you are looking to add quite a bit of capacity to your your 10″ MSI Wind U100, Lion Battery is going to be shipping 9-cell batteries for the U100 starting October 31, 2008.
It should increase the battery life of the U100 to over seven hours.
They are pre-order only (for now), have a black casing, and are selling for $179.95 (plus possible shipping charges).
Model: HLI-MU100XL/B
Made by: Mugen Power
mAh: 7800mAh
Weight: 0.46kg / 1 pound
In addition to the Wind U100, the battery also fits Wind clones, including the Advent 4211 and Medion Akoya Mini.
Link: Lion Battery
Thanks to Tim for the link.