Well, inetd is something completely different (not in Hijack), but also not really needed here for anything. (inetd is a super-daemon which binds to a lot of ports, and then spawns other daemons to handle incoming connections on those ports).
But telnetd is possible, though I don't see a compelling reason for it to be part of the Hijack kernel -- a userland telnetd app would be about the same size, and easier to play with once installed I suspect.
I once (like, a month ago) found some source code for a 100-line (C) telnetd from the 1980s -- no libraries or other package dependencies to speak of. Nice, compact, simple code. I even fiddled with maybe dropping it into Hijack at the time, but the syscalls work differently within the kernel and it was not to be.. but in userland, it should just drop in place and work. Lost the source though, and cannot for the life o'me remember where I found it.
But just go hunting with Google, for telnetd from say.. BSD 2.0 or something, and it'll be there. More recent versions are bloated with localization and extra security (eg. kerberos) and crap.. the older ones are nice lightweight simple code.
Cheers