I guess we can agree that S-Stripe should generally be a superior RGB. Personally, I can't think of a better layout that's not just a tweak of the four points that define the borders in the whole pixel, or simply a rotation.

Regarding PenTile, the original PenTile layout looks interesting:



Spatial resolution of the blue subpixels is exactly double that of that of the red and green subpixels. It's a conservative upgrade to RGB, but I guess subpixel budgets rule it out. However, rotating a subset of those pixels would make it possible to merge subpixels, this means trading pixels that fit neatly in a square grid for increased overall density.