This is not particularly interesting, but I wanted to record a couple of links to ChaosNET code for the PDP-10. The ChaosNET memo describes an ITS (Incompatible Time-Sharing System) interface, for which the code is somewhere in the ITS sources, and a Lisp Machine implementation, for which code is in the CADR sources and Symbolics code base, but also a TOPS-20/TENEX implementation, a VMS/VAX implementation, and a UNIX implementation. The UNIX implementation was documented by James E. Kulp for Symbolics, and the code seems to have survived. The TOPS-20/TENEX is harder to find, but it looks like BitSavers' Foonly archives have some files.
I have no idea whether this is at all related to the implementation the AI MEMO mentions.
A Google search turns up some interesting code (might be for the PDP-11 front end, for ITS)
CH10.defs1 "PDP-10 chaosnet interface definitions"
CH11.defs1 "CH11 Unibus chaosnet interface definitions"
CHSDEF.15 "Chaos net packet definition (for PDP-10s)"
KSNET.1 "Chaosnet interface on Unibus" (presumably for the KS10)
IOELEV.432 "i/o eleven"
NET.32 General ITS networking code