We just used ai.google instead of google.ai as the canonical domain name for Google's AI initiative for precisely this reason. (We run .google and you can see the source code at https://nomulus.foo )
It's like time traveling to 1987.
> We will email you a password after which you need to login and pay the $100, unless you are resident in Anguilla.
> After this we will send you a letter, fax and short text message (SMS) with codes on them. Please, be sure your information is correct so you can receive verifiaction codes. When you get these you need to login and enter them.
> We will also wait 3 months to make sure there is no problem with your credit card. But each successfully verification will decrease this period by one month, so if you pass all of them you do not need to wait 3 month.
Shame it's so arcane/expensive ($100 for account, then $100/2 years per domain) - there's a couple of joke domains I might have picked up if they were cheap enough (gomennas.ai / ebihara.ai [character from Persona4]).
I do appreciate that the TLD alone resolves though: http://ai./
God knows how widely a "ben@google" email address would work though. I'm going to guess not very.
That and apparently ICANN would frown upon such an implementation [1]