Relo questions: laptop

This isn’t really a “relocation” question, but it relates to my move.
After years of “creative diversity” at Sun (Sun Write/Paint/Draw, Applix, FrameMaker, StarOffice) I’m going to be entering a relatively conventional (MS Office, Outlook Exchange) IT environment at Amazon.com, and I’m going to have to get myself a new computer (or select one of the standard offerings from Amazon.com IT). Recently I’ve run various Macintoshes (iBook, PB12, PB15), as well as an Acer Ferrari 3400 for Solaris x64.
I like to use my laptop as my engineering notebook. It goes everywhere with me, and needs to be instantly available as soon as I open the lid. So it has to be light and small. On the other hand, when I’m at my desk I expect to be able to use a decent display at full resolution. Performance? Of course, but my experience is that disk speed is more critical than highly artificial CPU numbers. (And to get decent battery life the OS is going to be dialling back the CPU anyway.)
The problem is, my ideal system doesn’t seem to exist. Here are the key features I’m looking for, in priority order:

  1. Weighs less than 4 lbs
  2. 6-8 hours battery life
  3. 100GB 7200rpm hard disk
  4. Able to drive an external 20″ LCD via DVI
  5. WiFi, Bluetooth, USB 2.0 and FireWire
  6. DVD burner (detachable OK)
  7. Decent 3-D (Vista-compatible) graphics; not this shared-memory nonsense

Any suggestions?