Well, having sobered up after Christmas, the project is nearly completed. It is currently running at $000-$29C - 668 bytes. 3 of those are a 'hack' put in so I can load code in without typing it in, which wouldn't be in the final build.
Currently implemented commands are FETCH, GOTO, IF, LET, NEW, OUT, PRINT, STOP, VIEW and XECUTE. The reason for the renaming is I decode on the first character only (so I can't have IF and INPUT). So FETCH is INPUT, VIEW is LIST and XECUTE is RUN.
Currently outstanding are GOSUB/RETURN which means the interpreter is likely to come in in under 3 pages.
In places it is horribly wasteful of CPU time and data memory, but then it's designed to minimise code memory.
I appreciate the people who worked on the MCM/70 system - an 8008 APL Laptop from the early 1970s. It's an interesting machine to program for to put it mildly.