Namebase is a marketplace atop of the Handshake protocol. Puma Browser supports it natively, as well as NextDNS. If you really want your own TLD (or even to have your own name as a TLD), Namebase is the way to go (for now).
Maybe I should've added this information to my initial comment, I seem to have angered some folks.
Namebase is one in a long series of amateur projects (AlterNIC, OpenNIC, Namecoin...) which have aimed to create their own DNS roots.
Every single one of them has the exact same problem: the purpose of a domain name system is to agree upon naming. Alternate roots break that model, and any attempt to use them seriously immediately runs into massive interoperability problems (e.g. cannot send/receive email, cannot obtain SSL certificates, etc).
I haven't examined why others have failed so I have no rebuke on how "this time it's different."
However, I can speak to your last points.
Email sending between addresses utlizing Handshake domains has been demonstrated. I am unable to find any tweets but here's a video explaining how to do it[0]. Concerning security certificates, this is possibly via DANE rather than a centralized authority like LetsEncrypt. There is a tutorial[1] for that as well.
Regarding name collisions, Handshake's purpose isn't to replace legacy DNS, but to build atop it. It is for this reason that the Alexa top sites aren't available for bidding on Namebase. Again, I haven't looked at the amateur projects you've listed but it's possibly Handshake's focus is a key distinction.
> Email sending between addresses utlizing Handshake domains has been demonstrated.
Which fails to solve the problem of being able to interoperate with normal people on normal email servers.
> Concerning security certificates, this is possibly via DANE
DANE is dead. Nothing supports it, and there are no meaningful plans for that to change. Given that DNSSEC is still often dependent on RSA-1024 for security, it's not clear that DANE would even provide an adequate level of security.
> It is for this reason that the Alexa top sites aren't available for bidding on Namebase.
This is a bizarre assertion, given that Handshake is selling access to what are effectively TLDs, not domain names. A more believable explanation is simply that Handshake was attempting to avoid selling trademarked names associated with companies that would object to this.
Namebase is a marketplace atop of the Handshake protocol. Puma Browser supports it natively, as well as NextDNS. If you really want your own TLD (or even to have your own name as a TLD), Namebase is the way to go (for now).
Maybe I should've added this information to my initial comment, I seem to have angered some folks.