Asus will release 1151 motherboards with the Z170 chipset, but they cannot say when since Intel is being very tight with that information. I expect Skylake K's to be out before the end of the year, and possibly late in the year. Manufacturers already have samples and already have boards ready to go if they are worth their salt.
With the new chipset, I'd expect ROG MBs to be out shortly after the release, allowing feedback from boards 'in the wild.'
Personally, I'm waiting for an mITX 1151 board with an available M.2 gen3 x4 slot