If you’d want you could reach out to collaborate on the quicksyserver.
See that its approach seems collecting more data, though, not only to verify email-chat support for a known email address, but to return the XMPP addresses for phone numbers (hashes?), and maybe also return email, and email-chat support values.
Anyway, it would be a central service, and there might be other things still more important to fix.
([Wiki] Use-cases, chat rules and configuration options)