I built a PC this year and did some research.
Apparently Intel CPUs haven't progressed much beyond Sandy Bridge (2xxx). An unlocked (K-series) Intel i5 or i7 part from the past 5 years will have no trouble paired with a modern Nvidia 10 series or AMD 5 series GPU.
Intel just released a new generation (Coffee Lake) so now is the time, though they may not have made it into consumer products yet. Be wary that some "Coffee Lake" mobile components are rebadged Kaby Lakes from the previous generation.
I don't really know about gaming laptops though. Most are rebadged Clevo chassis? Dell Alienware and Razer probably build their own.
As Todd said, unless you don't have space for a monitor/keyboard/mouse, an mini-ITX build will always be superior to a laptop.
For keyboards, I mentioned a few brands previously. Post what you are interested in here and I can give my recommendations.