I'm in the market for a powerful CAD laptop, so it needs a good processor and good graphics. I'm not bothered about battery life. It seems difficult to find anything.
I'm sure there would be system integrators out there who customise "laptops" by using desktop CPUs. Google should turn-up a few options. The difficult bit might be finding one that fits your specific desires, I guess. Let us know how your search goes, cheers!
Any decent gaming laptop would fit your needs. Lots of those will have full-bore interchangeable CPUs and GPUs.