Sorry for the text only post. The new Kaby Lake I7-7700HQ start to pop up on some distributors sites (like this). Additionally, reports/rumors on early leaked benchmarks show up (here). The difference in these leaked benchmarks scores seems to be mostly thanks to the higher core clocks of the Kaby Lake CPUs and maybe some minor improvements in IPC (instructions per clock).
Around 10% advantage for the I7-7700HQ over the I7-6700HQ in this specific benchmark in the link. This is actually considerable difference, if the I7-7700HQ will be able to keep this difference in high load situations or games, in the case of laptops with a GTX 1070 and allow to squeeze more from the GPU.