Dell Inspiron XPS Gen. 3 Ever?

I will be leaving in August to go to college and I want to buy a DTR (DeskTop Replacement) laptop but I have a few questions so I can buy one at the best time. 

Right now I'm stuck between a Dell Inspiron XPS or the Inspiron 8600 but with Intel's PCI Express chipsets recently coming out I was wondering when Dell will be incorporating that technology into their line of laptops or at least make it available for the Inspiron XPS?

What I would like to have in my Dell laptop is a Pentium 4 3.4-3.6GHz or Pentium M 2.0GHz(Preferably a Pentium M). I'm also wondering when Dell will have the new Mobility Radeon X600 either in their Inspiron XPS or 8600.  http://www.ati.com/products/mobile.html

And lastly I don't understand why Dell doesn't make the ATI Mobility Radeon 9700 available in the Inspiron 8600.  Can anybody explain? If the Inspiron 8600 let you pick the Mobility Radeon 9700 I would definetly choose it over the Inspiron XPS whose battery is awful (The P4 processor is to blame) compared to the 8600. 

I would wet my pants if Dell came out with a laptop with a Pentium M 2.0GHz along with letting you choose the Mobility Radeon 9700 or the new X600.  Basically I'd love to have a Inspiron XPS but with a Pentium M 2.0GHz instead of the battery hogger P4.  You'd lose some performance but gain 1.5-2 hours of battery life.  A trade off I surely wouldn't mind.

If any of you can answer my scattered questions throughout I would be grateful.

Thanks!