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.
I, personally, would recommend an Alienware 17, but that may be a bit out of your price range. It is a good, high quality laptop, which will be able to use Microsoft Hololense.
An Alienware could be a good choice, but it is primarily a gaming computer. If the CAD software needs, or runs best on a "CAD card", then a gaming card may not work well.