$2500 Desktop build or HP Zbook 15

So my dilemma, I was thinking of waiting until Cyber Monday and see if I can catch a deal on building a beast workstation. Then I heard about the zbooks I kind of like the set up. Plus it has TB so I can use external raids and things of that nature. My only gripe is they really marked up the Intel Core i7-4800MQ and the systems only come configured with 4 to 16GB ram. I think the performance is negligible between the 4700MQ and 4800MQ but id still rather have that. The 4900 cost like 600 retail so I'm sure that is marked up super high too. 

So Should I buy the base model zbook for 1700? it comes with a Quadro K610M but only 1GB of DDR5 seems low to me and 4GB of ram? Then upgrade it with 4 sticks of Hyper 3k  8GB ram  a 128GB msata ssd and two 2TB hdds in raid 1? That will most likely put me at 2500 with aftermarket upgrades.


Or I could get the 1800 dollar model with the Quadro K1100m with 8 GB of ram then it might push me a lil closer to 3k. Having a laptop with TB and being able to edit where ever I go is super appealing I just want to buy the right machine. I really hate buyers remorse and this is a big purchase hopefully it will last me the next 3-5 years maybe more.

Any insight on the zbooks is appreciated. 

I would go for a desktop PC, not a laptop. If you go for a laptop, you will pay more for less. If you want to be very mobile with your gaming station, then I would go with a laptop, but otherwise go with a desktop.