Good laptop for 3d modelling?
Look on ebay for used, Dell Precision M6600 and M6800 laptops.
I've used them for years both at work and home.
You don't mention what CAD program will be used, but the Quadro cards in these computers is ideal for SolidWorks. I'm not sure if other CAD programs make as much use of a Quadro based card. It might be something to look into.