In looking at past releases, it appears we found out about the VE-1 on August 24th, which then had a pre-sale a week later on September 1st. That one is scheduled for release in January 2018. Not sure if that was a standard announcement, pre-sale, and release schedule though.
As for the VF-1A, it looks like it was announced last week (21st or 22nd), so a pre-sale should be soon: not sure if that means sometime this week, next week, or the following. It's a safe bet that the pre-sale date will be shared here before it takes place though.
This is a truly great community when it comes to announcements and on-sale dates.