For X99-E WS give it 1-2 weeks.
PS. For anyone asking about availability or using this as thread as reference, the dates given are for North America only. I only cover the NA region. For others you will need to contact your local ASUS rep/channels as each region may have different availability or launch time frames.
Kaby Lake overclocking guide hereASUS Z270 buyer's guide hereBroadwell-E overclocking guide read here