Mobility Guru has a comparison up, of the Dell Latitude X1 vs the Averatec AV1050, the Sony VAIO VGN-T350P, Fujitsu’s Lifebook P1510D and Lifebook B6110D, and Toshiba’s Portege R200.
This is a very comprehensive comparison – 17-pages worth of observations, charts, statistics, etc. One of the best you’ll find covering ultraportable laptops.