I think there is a value in upgrading the cheeseshop to use "verified maintainers" - it should be simple to do a first pass of "the person who signed the hash of this module has also verified they own the domain requests.kreitz.org by publishing that public key at that domains root" Even more useful might be domain/keys/kreitz/publickeylisting The key signing party is much harder to arrange but is easier to be confid…
That sounds useless. An attacker could verify that they own evilattacker.com & publish their malicious packages there.
I don't think a web of trust is the answer here, because it doesn't really matter if the attack is anonymous or not, and if only trusted people can publish packages, trust will be given more readily to encourage new programmers to contribute.
I think a reputation/review system is better, like docker search's star count, or metacpan's ++ rating.