I plan to use one of the new Thunderbolt 3 external GPU enclosures to connect a GTX 1070 to a laptop.
Obviously the video card of the laptop itself is unimportant, so I'm hoping to save some $$ by getting a laptop with a good CPU but a mediocre graphics card.
However, it has to have good cooling, because a CPU like a 6700HQ can still really cook. So, probably an ultra-thin laptop is not going to cut it. Good ventilation is crucial.
Btw, when I say cheap, I mean awesome quality, but less money than an awesome quality top-of-the-line gaming laptop. Probably an ASUS, Gigabyte, Lenovo or Alienware, and something sporting a GTX 965 or worse would probably be fit the bill.
I'd really like to see at least one option from the above brands. I probably should have said "must be". Also it should be an HQ or HK CPU or better.
Budget is relative. If there's a Gigabyte laptop which fits the bill and is cheaper than the equivalent Gigabyte laptop with beefy graphics, then we're winning.