[thwarted]

Inetd only did TCP socket activation, not of unix sockets, though.

False.

http://manpages.ubuntu.com/manpages/hardy/man8/inetd.8.html

    The service name entry is the name of a valid service in the file
    /etc/services. … For UNIX domain sockets this field specifies the
    path name of the socket.


    The protocol must be a valid protocol as given in /etc/protocols.
    Examples might be “unix”, “tcp” or “udp”. … A protocol of “unix”
    is used to specify a socket in the UNIX domain.

xinetd does not appear to support this feature.

[icebraining]

Oops, you're right, I misread an article about socket activation.