I find most people's reactions in this thread a bit strange. You might want to think about the shape of the iPhone 6 more before complaining about glass protector sizes and what suppliers are trying to come up with. I bought a Spigen tough armor case and the first tempered glass protector I could find. Some observations:
1. The cover obviously only covers the flat area of the screen, which seems perfectly understandable to me. I put mine on half a mm too high (so now it overhangs a tiny bit), and now air is already coming in under the top, which means dust later on. So an overlapping protector is never going to work.
2. Because the screen curves down on the sides, the case edges are lower than we were used to on older models (i.e. less room between screen and table when you leave the iPhone upside down). The case clamps on to the screen at a lower point, leaving a few mm between the case edge and tempered glass, for me about 3-4mm. I'm guessing this will vary, but only because of the case. The gap area is curved however, so both height and width need to be filled up somehow, but in various sizes to reach the case edge. I'd think that rules out a generic protector.
3. Points 1 and 2 together will make it very hard to come up with a curved glass protection that will fit all cases. I'm guessing it will be a lot harder/more expensive to create perfectly curved glass that will stick to the iPhone, but that will be the ideal solution. But then we're probably talking molding instead of cutting protectors from a sheet. In any case it will mean a higher price for protectors.
I don't think overlapping protectors are going to work since you need to know how much space there will be from where the curve starts to the edge of the case. For now I'm going to live with the 3-4mm gap and see what people are going to come up with.