Sorry to tell you but there is none. Almost all new slick PC laptops with 4K displays and the goodness that blow Mac Book Pro in every way imaginable are simply not going to work with OSX because they all use Optimus now.
Unless you want to go with something like Sager 10 pound monster laptop that uses desktop level GPU graphics without Optimus technology.. you are going to have hard time finding any laptop on the market that will fit your requirements to replace Mac Book Pro.
The problem, as I already stated is "Optimus" technology relating to Intel chipset and new GTX cards. You can only use OSX with the integrated GPU and if you can't turn off IGD and run Nvidia card alone (in most cases there is no way to do that) you are out of luck. On most new laptops it isn't even possible to turn run discrete GPU (that's why most BIOSes removed the option) because the way Optimus (IGD + dedicated card) work is that the dedicated GPU is going through the IGD to send the signal to the monitor so when the less GPU intensive operations happen while you work Optimus switches discrete graphics on and off as needed without interrupting your experience and sends information back through IGD that's connected to the display.
I have been reading up for weeks now. From slick as hell new Dell 13.3" full frame 4K kick ass all aluminum laptop to this beauty
http://www.aorus.com/x3plus.aspx to many many others.. none of them use a fully dedicated GPU and all use Optimus.
I looked at everything:
ASUS, ACER, Gigabyte, Sager, Dell, MSI (Ghost 4K series) Lenovo etc etc.. they all use Optimus. Only ones that don't are a few monster desktop replacement 17.3" laptops that way like almost 10 pounds from Sager and ASUS if I remember correctly.
Plus, all these new slick beautiful laptops are getting pricer now on the PC side. Though they'll offer amazing tech and displays and so on, they are all running around $2k.
Personally, I'm waiting for MBP refresh and I'll just get that (probably will be about 700-800 bucks more than PC variants).. . First time I will actually buy a Mac Book Pro over a PC hackintosh laptop (currently have ASUS G750JX GTX 770M 32gb of ram with 2 SSDs and 1TB storage) and I love it but it's heavy and very cumbersome and I need something thinner.