In nV's case, custom everything.
As far as it goes for the 1080,
this video shows that even with decent after market cooling and the GPU at 50°C load, it can't go past 2-2.1GHz without throttling. That could be due to the gimped power delivery:
Come on, that VRM could be much beefier if they wanted it to be. Almost half is unpopulated. Hell, the board seems to be able to take another 8 pin power connector! If you're going all the way to sell the classic reference design as the "founder's edition", have it use the blower (that can't even compete with aftermarket cooling, unless you do need the hot air directly exhausted) and rip people off even more with an extra $100 apart from selling Gx104 chips at Gx100 prices for the past few generations, at least have the decency to sell a fully populated board that can take a beating, especially for those who are going to watercool your reference design.
I remember the GTX 590, its reference board was so weak these cards were blowing their VRMs up with a little OC. That's where nV probably found the bottom of how much they could get away with saving a penny here and there with the board.
There's also the usual BIOS limits nV puts in place that are a nuisance if you have a well cooled card. This, thankfully, isn't a problem once bios modders get their hands on the stuff.
So yeah, unless you can't wait for decent custom boards that are also going to be probably cheaper than the rip off edition, you'll be getting much more for your money. Those rumors of custom boards doing 2.4-2.5GHz on water/decent air cooling that were circulating the past week or so are probably true consdering all of this. If partners are releasing their custom cards on the same day as the rip off edition is available, it's gonna be fun seeing the reference boards drop in price since nobody's buying them.
For AMD, their reference boards historically seem to be better built and do have potential for use with a waterblock. nV could learn a thing or two from them on this regard. nV's reference blower is ok, they just can't pretend to charge more for it over an aftermarket card that is better in nearly every way.