Tom Rindfleisch kindly supplied a set of TENEX Interlisp files from a system dump of the SUMEX-AIM <lisp> directory as of January 31, 1982. Tom notes:
This version of Interlisp should be both TENEX and TOPS20 compatible. It came at a time when lots of work was going on to port Interlisp to other environments, including the VAX and the new personal Lisp machines (Dolphins, etc.). This means little was changing in the TENEX/TOPS20 version.
There are links to these files here.
Speaking of TENEX Interlisp, TWENEX.ORG is offering free TENEX accounts on a simulated KL10B and they seem to have a version of Interlisp installed. I plan to investigate.
[Edited 10 May 2014: community.computerhistory.org/scc/projects/LISP/index.html#INTERLISP_ => www.softwarepreservation.org/projects/LISP/interlisp_family/#INTERLISP_.]