If Nintendo needed to dedicate dye space to Maxwell architecture, im not so sure they wouldn't just stick with the architecture. Yes, I know that would be extremely unpopular here, but if a more elegant solution cant be found or is far more expensive to implement, im not convinced they wouldn't stick with the same architecture. The reduced performance from the older architecture would be offset by not having any wasted space for BC. The Tegra X1 also had quite a bit of useless dye space for non gaming related hardware. On the 7nm process, something like 1024 Cuda cores would fit within the dye space limitations. Four Tegra X1's duck taped together. I cant shake the feeling that this is not only possible, but because of Nintendo's history, its actually plausible.