Too bad it has to run XP Pro.

For a moderately priced system, a G4 iBook would fit the bill quite nicely. At the higher end a G4 Powerbook would be perfect.

Running SQL on Mac OS X is a dream, as is MS Office. Making the box a server requires a few clicks.

All your other requirements could be met by these two machines at a price lower or at least competitive with a Thinkpad.

On top of that, your computer will go to sleep properly and wake up instantly when opened, Rendezvous will automatically detect all network connections for you, without requiring much, if any setup, most drivers are built into the OS, the computer will remain useful about 25% longer than a Wintel system, and, for technical users, you have complete access at a unix command line level.

I found it interesting that the vast majority of laptops floating around JPL in Nova's Mars documentary that aired last week were Powerbooks. I watched a trading shop switch from Thinkpads to Powerbooks with Cinema Displays and rackmount XServes over the course of a few months after their IBM hardware couldn't support their needs as well.

If you're at all flexible on the OS criterion, the most elegant solution would definitely be the Powerbook: thinnest, lightest, 5 hour battery life, with all the other specs you desire.