M590K 19" notebook

Hi, I'm in process of buying a high-end laptop. I wanted to buy a 17" pentium M with Nvidia 7800Gtx 256Mo and 2Gb DDR.

But I found out that Clevo and Nvidia are going to release a new 19" platform including a dual Nvidia 7800Gtx 256Mo (SLI) with the Turion 64 and sata-2 120Gb 7200rpm HD.

The price and the weight isn't an issue. And I need something that will run CAD (Autocad, Catia, ProEngineer,...) programm in 3-4 years from now.

My main problem would be the battery life. I would need it for at least a good 3hours.

What do you think the battery life would be considering those facts:
- 19" monitor to power
- dual hardcore GPUs (for mobile)
- 64bit ML (25w)
- big HD and 7200rpm

if you compare to the version I originally wanted:
- 17"
- single hardcore GPU (mobile)
- 32bit (27w)
- big HD and 7200 rpm

this notebook is rated for 3.5hours on single battery and 6 on dual batteries.

what do you think?