I would suggest a desktop replacement gaming laptop, very easy to go mobile with it and you can handle some pretty solid games graphics wise on one depending on what you get, like mines, I got an asus, very good for gaming.

Well, this all depends on what you want, each has one big pro against the other:

Laptop: Portability
You can play the game anywhere, not just at the computer desk.

Desktop: Expandability
You can more easily upgrade the graphics card, memory and such, so you can extend its 'useful lifetime' for less than it would cost to replace a laptop with a better model.

Honestly, gaming is bad for laptops. gaming laptops are literally twice as expensive as an equivalent desktop. and they wear out WAY faster. cause theyre more compact and parts are pressed closer together, they heat up more and wear out heat sinks and the connections in the laptop a lot faster in a desktop.

my current gaming desktop, total cost me maybe 500 bucks, built it myself, and it plays any modern game on max settings without any hesitation.

a gaming laptop is more portable and more convenient, but your gonna get a lot more of what your moneys worth in a desktop. both when it comes to upgrading longevity, durability, and price

Where can I get a Custom Comp?

well to get the best deal, you have to buy the individual parts and either get a friend or do it yourself, put them together. https://www.tigerdirect.com is where i buy my stuff. there or https://www.newegg.com

I 2nd this notion!

And if I don't know how/anyone who can?

look up guides online., and make sure you get stuff with warrentys. honestly it sounds super scary, but if your careful and read instructions well, its really easy

Bavarian pretty much put everything I was going to say. If you're going to be on the go a lot and want to play anywhere, get a laptop. If you're gonna play games only while at home, get a custom built comp. The options are nearly limitless, the only limit is your wallet.

Keep in mind when you go mobile the technology is designed for optimum battery life not speed. Also since laptops are in smaller packages and must make less heat so it does not overheat, to make less heat they have to use lower power parts. Laptop parts even if the same model as desktop parts are no where near the performance of the desktop part. Here are the specs of the cards on the market to compare

desktop 680 http://www.geforce.com/hardware/des.....specifications
laptop 680 http://www.geforce.com/hardware/not.....specifications