I tried out 2 new MSI gaming laptops in the shop last weekend, one was a 1070 SLI, the other a single 1080, but both didn't have that huge cooling system either, and were standard laptop size (well, sort of, one was 18.4"). While not as fast as what Asus is building, they are more portable for sure, and pretty close in terms of performance - IMO at least, as I had a 1080 SLI system I've posted here before, and I find fewer and fewer games take advantage of SLI, even using nVidia Inspector and every other trick to try and boost SLI performance, it's mostly out of ones hands and in the hands of those creating the SLI profile. I say had as I sold one of the 1080 cards, and bought a new Titan for that system instead. Also, SLI doesn't function much with VR yet.
http://www.memoryexpress.com/Products/MX63416Linus Tech Tips did a preview of an early of this Asus system in the OP not long ago, and the good news is it'll still work without the cooling rig attachment, it just dials down performance, so IMO it's a great option for frequent travelers, as you can leave part of it in your checked baggage, and take the smaller/slimmer main unit to your seat and still be able to use it, then go desktop-equivalent once you've hit your hotel or destination.
Performance laptops will always cost more, but if you travel a lot and like to game still, it's nice having the option. There are some smaller sticks available too, but it'd be nice to see a travel sized hotas with a rocker throttle for the rudder, even though that market is minuscule to be sure.
A LOT of 970 and 980M equipped Asus and MSI gaming laptops going for huge discounts up here as black Friday approaches, one 1600$ loaded 17.3 970 is slatted for $700 dollars off (CDN dollars). I'm glad we swapped out 970 for our 1060 laptop when we did, as their value is about to plunge a lot.