Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.
It's been mentioned for lga1151 it is possible up to 64gb but cant imagine the cost of 16gb single sticks. Whether or not 16gb x 4 is supported in the final z170 boards who knows.
Looking at what DDR4 memory you can actually buy right now, Newegg only has sets of eight 16GB sticks at $200 per stick (that's $1600 for the set); there are no single sticks or sets of 2 or 4 sticks available, so just getting 16GB sticks at all appears to be an issue.
So, you may have trouble getting more than 32GB of DDR4 into a 4-slot motherboard for awhile.
The skylake Xeon E3 supports 64gb on lga1151 with ddr4 so it's possible other skylake-s models do too. 64gb seems like a very expensive requirement. It might be cheaper to scale out instead of up if licensing isn't an issue.